text: //
  //  AsyncSocket.h
  //
  //  This class is in the public domain.
  //  Originally created by Dustin Voss on Wed Jan 29 2003.
  //  Updated and maintained by Deusty Designs and the Mac development community.
  //
  //  http://code.google.com/p/cocoaasyncsocket/
  //
  
  #import <Foundation/Foundation.h>
  
  @class AsyncSocket;
  @class AsyncReadPacket;
  @class AsyncWritePacket;
  
  extern NSString *const AsyncSocketException;
  extern NSString *const AsyncSocketErrorDomain;
  
  enum AsyncSocketError
  {
      AsyncSocketCFSocketError = kCFSocketError,	// From CFSocketError enum.
      AsyncSocketNoError = 0,						// Never used.
      AsyncSocketCanceledError,					// onSocketWillConnect: returned NO.
      AsyncSocketConnectTimeoutError,
      AsyncSocketReadMaxedOutError,               // Reached set maxLength without completing
      AsyncSocketReadTimeoutError,
      AsyncSocketWriteTimeoutError
  };
  typedef enum AsyncSocketError AsyncSocketError;
  
  @protocol AsyncSocketDelegate
  @optional
  
  /**
   * In the event of an error, the socket is closed.
   * You may call "unreadData" during this call-back to get the last bit of data off the socket.
   * When connecting, this delegate method may be called
   * before"onSocket:didAcceptNewSocket:" or "onSocket:didConnectToHost:".
   **/
  - (void)onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err;
  
  /**
   * Called when a socket disconnects with or without error.  If you want to release a socket after it disconnects,
   * do so here. It is not safe to do that during "onSocket:willDisconnectWithError:".
   *
   * If you call the disconnect method, and the socket wasn't already disconnected,
   * this delegate method will be called before the disconnect method returns.
   **/
  - (void)onSocketDidDisconnect:(AsyncSocket *)sock;
  
  /**
   * Called when a socket accepts a connection.  Another socket is spawned to handle it. The new socket will have
   * the same delegate and will call "onSocket:didConnectToHost:port:".
   **/
  - (void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket;
  
  /**
   * Called when a new socket is spawned to handle a connection.  This method should return the run-loop of the
   * thread on which the new socket and its delegate should operate. If omitted, [NSRunLoop currentRunLoop] is used.
   **/
  - (NSRunLoop *)onSocket:(AsyncSocket *)sock wantsRunLoopForNewSocket:(AsyncSocket *)newSocket;
  
  /**
   * Called when a socket is about to connect. This method should return YES to continue, or NO to abort.
   * If aborted, will result in AsyncSocketCanceledError.
   *
   * If the connectToHost:onPort:error: method was called, the delegate will be able to access and configure the
   * CFReadStream and CFWriteStream as desired prior to connection.
   *
   * If the connectToAddress:error: method was called, the delegate will be able to access and configure the
   * CFSocket and CFSocketNativeHandle (BSD socket) as desired prior to connection. You will be able to access and
   * configure the CFReadStream and CFWriteStream in the onSocket:didConnectToHost:port: method.
   **/
  - (BOOL)onSocketWillConnect:(AsyncSocket *)sock;
  
  /**
   * Called when a socket connects and is ready for reading and writing.
   * The host parameter will be an IP address, not a DNS name.
   **/
  - (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port;
  
  /**
   * Called when a socket has completed reading the requested data into memory.
   * Not called if there is an error.
   **/
  - (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag;
  
  /**
   * Called when a socket has read in data, but has not yet completed the read.
   * This would occur if using readToData: or readToLength: methods.
   * It may be used to for things such as updating progress bars.
   **/
  - (void)onSocket:(AsyncSocket *)sock didReadPartialDataOfLength:(NSUInteger)partialLength tag:(long)tag;
  
  /**
   * Called when a socket has completed writing the requested data. Not called if there is an error.
   **/
  - (void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag;
  
  /**
   * Called when a socket has written some data, but has not yet completed the entire write.
   * It may be used to for things such as updating progress bars.
   **/
  - (void)onSocket:(AsyncSocket *)sock didWritePartialDataOfLength:(NSUInteger)partialLength tag:(long)tag;
  
  /**
   * Called if a read operation has reached its timeout without completing.
   * This method allows you to optionally extend the timeout.
   * If you return a positive time interval (> 0) the read's timeout will be extended by the given amount.
   * If you don't implement this method, or return a non-positive time interval (<= 0) the read will timeout as usual.
   *
   * The elapsed parameter is the sum of the original timeout, plus any additions previously added via this method.
   * The length parameter is the number of bytes that have been read so far for the read operation.
   *
   * Note that this method may be called multiple times for a single read if you return positive numbers.
   **/
  - (NSTimeInterval)onSocket:(AsyncSocket *)sock
    shouldTimeoutReadWithTag:(long)tag
                     elapsed:(NSTimeInterval)elapsed
                   bytesDone:(NSUInteger)length;
  
  /**
   * Called if a write operation has reached its timeout without completing.
   * This method allows you to optionally extend the timeout.
   * If you return a positive time interval (> 0) the write's timeout will be extended by the given amount.
   * If you don't implement this method, or return a non-positive time interval (<= 0) the write will timeout as usual.
   *
   * The elapsed parameter is the sum of the original timeout, plus any additions previously added via this method.
   * The length parameter is the number of bytes that have been written so far for the write operation.
   *
   * Note that this method may be called multiple times for a single write if you return positive numbers.
   **/
  - (NSTimeInterval)onSocket:(AsyncSocket *)sock
   shouldTimeoutWriteWithTag:(long)tag
                     elapsed:(NSTimeInterval)elapsed
                   bytesDone:(NSUInteger)length;
  
  /**
   * Called after the socket has successfully completed SSL/TLS negotiation.
   * This method is not called unless you use the provided startTLS method.
   *
   * If a SSL/TLS negotiation fails (invalid certificate, etc) then the socket will immediately close,
   * and the onSocket:willDisconnectWithError: delegate method will be called with the specific SSL error code.
   **/
  - (void)onSocketDidSecure:(AsyncSocket *)sock;
  
  @end
  
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  #pragma mark -
  ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
  
  @interface AsyncSocket : NSObject
  {
      CFSocketNativeHandle theNativeSocket4;
      CFSocketNativeHandle theNativeSocket6;
      
      CFSocketRef theSocket4;            // IPv4 accept or connect socket
      CFSocketRef theSocket6;            // IPv6 accept or connect socket
      
      CFReadStreamRef theReadStream;
      CFWriteStreamRef theWriteStream;
      
      CFRunLoopSourceRef theSource4;     // For theSocket4
      CFRunLoopSourceRef theSource6;     // For theSocket6
      CFRunLoopRef theRunLoop;
      CFSocketContext theContext;
      NSArray *theRunLoopModes;
      
      NSTimer *theConnectTimer;
      
      NSMutableArray *theReadQueue;
      AsyncReadPacket *theCurrentRead;
      NSTimer *theReadTimer;
      NSMutableData *partialReadBuffer;
      
      NSMutableArray *theWriteQueue;
      AsyncWritePacket *theCurrentWrite;
      NSTimer *theWriteTimer;
      
      id theDelegate;
      UInt16 theFlags;
      
      long theUserData;
  }
  
  - (id)init;
  - (id)initWithDelegate:(id)delegate;
  - (id)initWithDelegate:(id)delegate userData:(long)userData;
  
  /* String representation is long but has no "\n". */
  - (NSString *)description;
  
  /**
   * Use "canSafelySetDelegate" to see if there is any pending business (reads and writes) with the current delegate
   * before changing it.  It is, of course, safe to change the delegate before connecting or accepting connections.
   **/
  - (id)delegate;
  - (BOOL)canSafelySetDelegate;
  - (void)setDelegate:(id)delegate;
  
  /* User data can be a long, or an id or void * cast to a long. */
  - (long)userData;
  - (void)setUserData:(long)userData;
  
  /* Don't use these to read or write. And don't close them either! */
  - (CFSocketRef)getCFSocket;
  - (CFReadStreamRef)getCFReadStream;
  - (CFWriteStreamRef)getCFWriteStream;
  
  // Once one of the accept or connect methods are called, the AsyncSocket instance is locked in
  // and the other accept/connect methods can't be called without disconnecting the socket first.
  // If the attempt fails or times out, these methods either return NO or
  // call "onSocket:willDisconnectWithError:" and "onSockedDidDisconnect:".
  
  // When an incoming connection is accepted, AsyncSocket invokes several delegate methods.
  // These methods are (in chronological order):
  // 1. onSocket:didAcceptNewSocket:
  // 2. onSocket:wantsRunLoopForNewSocket:
  // 3. onSocketWillConnect:
  //
  // Your server code will need to retain the accepted socket (if you want to accept it).
  // The best place to do this is probably in the onSocket:didAcceptNewSocket: method.
  //
  // After the read and write streams have been setup for the newly accepted socket,
  // the onSocket:didConnectToHost:port: method will be called on the proper run loop.
  //
  // Multithreading Note: If you're going to be moving the newly accepted socket to another run
  // loop by implementing onSocket:wantsRunLoopForNewSocket:, then you should wait until the
  // onSocket:didConnectToHost:port: method before calling read, write, or startTLS methods.
  // Otherwise read/write events are scheduled on the incorrect runloop, and chaos may ensue.
  
  /**
   * Tells the socket to begin listening and accepting connections on the given port.
   * When a connection comes in, the AsyncSocket instance will call the various delegate methods (see above).
   * The socket will listen on all available interfaces (e.g. wifi, ethernet, etc)
   **/
  - (BOOL)acceptOnPort:(UInt16)port error:(NSError **)errPtr;
  
  /**
   * This method is the same as acceptOnPort:error: with the additional option
   * of specifying which interface to listen on. So, for example, if you were writing code for a server that
   * has multiple IP addresses, you could specify which address you wanted to listen on.  Or you could use it
   * to specify that the socket should only accept connections over ethernet, and not other interfaces such as wifi.
   * You may also use the special strings "localhost" or "loopback" to specify that
   * the socket only accept connections from the local machine.
   *
   * To accept connections on any interface pass nil, or simply use the acceptOnPort:error: method.
   **/
  - (BOOL)acceptOnInterface:(NSString *)interface port:(UInt16)port error:(NSError **)errPtr;
  
  /**
   * Connects to the given host and port.
   * The host may be a domain name (e.g. "deusty.com") or an IP address string (e.g. "192.168.0.2")
   **/
  - (BOOL)connectToHost:(NSString *)hostname onPort:(UInt16)port error:(NSError **)errPtr;
  
  /**
   * This method is the same as connectToHost:onPort:error: with an additional timeout option.
   * To not time out use a negative time interval, or simply use the connectToHost:onPort:error: method.
   **/
  - (BOOL)connectToHost:(NSString *)hostname
                 onPort:(UInt16)port
            withTimeout:(NSTimeInterval)timeout
                  error:(NSError **)errPtr;
  
  /**
   * Connects to the given address, specified as a sockaddr structure wrapped in a NSData object.
   * For example, a NSData object returned from NSNetService's addresses method.
   *
   * If you have an existing struct sockaddr you can convert it to a NSData object like so:
   * struct sockaddr sa  -> NSData *dsa = [NSData dataWithBytes:&remoteAddr length:remoteAddr.sa_len];
   * struct sockaddr *sa -> NSData *dsa = [NSData dataWithBytes:remoteAddr length:remoteAddr->sa_len];
   **/
  - (BOOL)connectToAddress:(NSData *)remoteAddr error:(NSError **)errPtr;
  
  /**
   * This method is the same as connectToAddress:error: with an additional timeout option.
   * To not time out use a negative time interval, or simply use the connectToAddress:error: method.
   **/
  - (BOOL)connectToAddress:(NSData *)remoteAddr withTimeout:(NSTimeInterval)timeout error:(NSError **)errPtr;
  
  - (BOOL)connectToAddress:(NSData *)remoteAddr
       viaInterfaceAddress:(NSData *)interfaceAddr
               withTimeout:(NSTimeInterval)timeout
                     error:(NSError **)errPtr;
  
  /**
   * Disconnects immediately. Any pending reads or writes are dropped.
   * If the socket is not already disconnected, the onSocketDidDisconnect delegate method
   * will be called immediately, before this method returns.
   *
   * Please note the recommended way of releasing an AsyncSocket instance (e.g. in a dealloc method)
   * [asyncSocket setDelegate:nil];
   * [asyncSocket disconnect];
   * [asyncSocket release];
   **/
  - (void)disconnect;
  
  /**
   * Disconnects after all pending reads have completed.
   * After calling this, the read and write methods will do nothing.
   * The socket will disconnect even if there are still pending writes.
   **/
  - (void)disconnectAfterReading;
  
  /**
   * Disconnects after all pending writes have completed.
   * After calling this, the read and write methods will do nothing.
   * The socket will disconnect even if there are still pending reads.
   **/
  - (void)disconnectAfterWriting;
  
  /**
   * Disconnects after all pending reads and writes have completed.
   * After calling this, the read and write methods will do nothing.
   **/
  - (void)disconnectAfterReadingAndWriting;
  
  /* Returns YES if the socket and streams are open, connected, and ready for reading and writing. */
  - (BOOL)isConnected;
  
  /**
   * Returns the local or remote host and port to which this socket is connected, or nil and 0 if not connected.
   * The host will be an IP address.
   **/
  - (NSString *)connectedHost;
  - (UInt16)connectedPort;
  
  - (NSString *)localHost;
  - (UInt16)localPort;
  
  /**
   * Returns the local or remote address to which this socket is connected,
   * specified as a sockaddr structure wrapped in a NSData object.
   *
   * See also the connectedHost, connectedPort, localHost and localPort methods.
   **/
  - (NSData *)connectedAddress;
  - (NSData *)localAddress;
  
  /**
   * Returns whether the socket is IPv4 or IPv6.
   * An accepting socket may be both.
   **/
  - (BOOL)isIPv4;
  - (BOOL)isIPv6;
  
  // The readData and writeData methods won't block (they are asynchronous).
  //
  // When a read is complete the onSocket:didReadData:withTag: delegate method is called.
  // When a write is complete the onSocket:didWriteDataWithTag: delegate method is called.
  //
  // You may optionally set a timeout for any read/write operation. (To not timeout, use a negative time interval.)
  // If a read/write opertion times out, the corresponding "onSocket:shouldTimeout..." delegate method
  // is called to optionally allow you to extend the timeout.
  // Upon a timeout, the "onSocket:willDisconnectWithError:" method is called, followed by "onSocketDidDisconnect".
  //
  // The tag is for your convenience.
  // You can use it as an array index, step number, state id, pointer, etc.
  
  /**
   * Reads the first available bytes that become available on the socket.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   **/
  - (void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag;
  
  /**
   * Reads the first available bytes that become available on the socket.
   * The bytes will be appended to the given byte buffer starting at the given offset.
   * The given buffer will automatically be increased in size if needed.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   * If the buffer if nil, the socket will create a buffer for you.
   *
   * If the bufferOffset is greater than the length of the given buffer,
   * the method will do nothing, and the delegate will not be called.
   *
   * If you pass a buffer, you must not alter it in any way while AsyncSocket is using it.
   * After completion, the data returned in onSocket:didReadData:withTag: will be a subset of the given buffer.
   * That is, it will reference the bytes that were appended to the given buffer.
   **/
  - (void)readDataWithTimeout:(NSTimeInterval)timeout
                       buffer:(NSMutableData *)buffer
                 bufferOffset:(NSUInteger)offset
                          tag:(long)tag;
  
  /**
   * Reads the first available bytes that become available on the socket.
   * The bytes will be appended to the given byte buffer starting at the given offset.
   * The given buffer will automatically be increased in size if needed.
   * A maximum of length bytes will be read.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   * If the buffer if nil, a buffer will automatically be created for you.
   * If maxLength is zero, no length restriction is enforced.
   *
   * If the bufferOffset is greater than the length of the given buffer,
   * the method will do nothing, and the delegate will not be called.
   *
   * If you pass a buffer, you must not alter it in any way while AsyncSocket is using it.
   * After completion, the data returned in onSocket:didReadData:withTag: will be a subset of the given buffer.
   * That is, it will reference the bytes that were appended to the given buffer.
   **/
  - (void)readDataWithTimeout:(NSTimeInterval)timeout
                       buffer:(NSMutableData *)buffer
                 bufferOffset:(NSUInteger)offset
                    maxLength:(NSUInteger)length
                          tag:(long)tag;
  
  /**
   * Reads the given number of bytes.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   *
   * If the length is 0, this method does nothing and the delegate is not called.
   **/
  - (void)readDataToLength:(NSUInteger)length withTimeout:(NSTimeInterval)timeout tag:(long)tag;
  
  /**
   * Reads the given number of bytes.
   * The bytes will be appended to the given byte buffer starting at the given offset.
   * The given buffer will automatically be increased in size if needed.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   * If the buffer if nil, a buffer will automatically be created for you.
   *
   * If the length is 0, this method does nothing and the delegate is not called.
   * If the bufferOffset is greater than the length of the given buffer,
   * the method will do nothing, and the delegate will not be called.
   *
   * If you pass a buffer, you must not alter it in any way while AsyncSocket is using it.
   * After completion, the data returned in onSocket:didReadData:withTag: will be a subset of the given buffer.
   * That is, it will reference the bytes that were appended to the given buffer.
   **/
  - (void)readDataToLength:(NSUInteger)length
               withTimeout:(NSTimeInterval)timeout
                    buffer:(NSMutableData *)buffer
              bufferOffset:(NSUInteger)offset
                       tag:(long)tag;
  
  /**
   * Reads bytes until (and including) the passed "data" parameter, which acts as a separator.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   *
   * If you pass nil or zero-length data as the "data" parameter,
   * the method will do nothing, and the delegate will not be called.
   *
   * To read a line from the socket, use the line separator (e.g. CRLF for HTTP, see below) as the "data" parameter.
   * Note that this method is not character-set aware, so if a separator can occur naturally as part of the encoding for
   * a character, the read will prematurely end.
   **/
  - (void)readDataToData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag;
  
  /**
   * Reads bytes until (and including) the passed "data" parameter, which acts as a separator.
   * The bytes will be appended to the given byte buffer starting at the given offset.
   * The given buffer will automatically be increased in size if needed.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   * If the buffer if nil, a buffer will automatically be created for you.
   *
   * If the bufferOffset is greater than the length of the given buffer,
   * the method will do nothing, and the delegate will not be called.
   *
   * If you pass a buffer, you must not alter it in any way while AsyncSocket is using it.
   * After completion, the data returned in onSocket:didReadData:withTag: will be a subset of the given buffer.
   * That is, it will reference the bytes that were appended to the given buffer.
   *
   * To read a line from the socket, use the line separator (e.g. CRLF for HTTP, see below) as the "data" parameter.
   * Note that this method is not character-set aware, so if a separator can occur naturally as part of the encoding for
   * a character, the read will prematurely end.
   **/
  - (void)readDataToData:(NSData *)data
             withTimeout:(NSTimeInterval)timeout
                  buffer:(NSMutableData *)buffer
            bufferOffset:(NSUInteger)offset
                     tag:(long)tag;
  
  /**
   * Reads bytes until (and including) the passed "data" parameter, which acts as a separator.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   *
   * If maxLength is zero, no length restriction is enforced.
   * Otherwise if maxLength bytes are read without completing the read,
   * it is treated similarly to a timeout - the socket is closed with a AsyncSocketReadMaxedOutError.
   * The read will complete successfully if exactly maxLength bytes are read and the given data is found at the end.
   *
   * If you pass nil or zero-length data as the "data" parameter,
   * the method will do nothing, and the delegate will not be called.
   * If you pass a maxLength parameter that is less than the length of the data parameter,
   * the method will do nothing, and the delegate will not be called.
   *
   * To read a line from the socket, use the line separator (e.g. CRLF for HTTP, see below) as the "data" parameter.
   * Note that this method is not character-set aware, so if a separator can occur naturally as part of the encoding for
   * a character, the read will prematurely end.
   **/
  - (void)readDataToData:(NSData *)data withTimeout:(NSTimeInterval)timeout maxLength:(NSUInteger)length tag:(long)tag;
  
  /**
   * Reads bytes until (and including) the passed "data" parameter, which acts as a separator.
   * The bytes will be appended to the given byte buffer starting at the given offset.
   * The given buffer will automatically be increased in size if needed.
   * A maximum of length bytes will be read.
   *
   * If the timeout value is negative, the read operation will not use a timeout.
   * If the buffer if nil, a buffer will automatically be created for you.
   *
   * If maxLength is zero, no length restriction is enforced.
   * Otherwise if maxLength bytes are read without completing the read,
   * it is treated similarly to a timeout - the socket is closed with a AsyncSocketReadMaxedOutError.
   * The read will complete successfully if exactly maxLength bytes are read and the given data is found at the end.
   *
   * If you pass a maxLength parameter that is less than the length of the data parameter,
   * the method will do nothing, and the delegate will not be called.
   * If the bufferOffset is greater than the length of the given buffer,
   * the method will do nothing, and the delegate will not be called.
   *
   * If you pass a buffer, you must not alter it in any way while AsyncSocket is using it.
   * After completion, the data returned in onSocket:didReadData:withTag: will be a subset of the given buffer.
   * That is, it will reference the bytes that were appended to the given buffer.
   *
   * To read a line from the socket, use the line separator (e.g. CRLF for HTTP, see below) as the "data" parameter.
   * Note that this method is not character-set aware, so if a separator can occur naturally as part of the encoding for
   * a character, the read will prematurely end.
   **/
  - (void)readDataToData:(NSData *)data
             withTimeout:(NSTimeInterval)timeout
                  buffer:(NSMutableData *)buffer
            bufferOffset:(NSUInteger)offset
               maxLength:(NSUInteger)length
                     tag:(long)tag;
  
  /**
   * Writes data to the socket, and calls the delegate when finished.
   *
   * If you pass in nil or zero-length data, this method does nothing and the delegate will not be called.
   * If the timeout value is negative, the write operation will not use a timeout.
   **/
  - (void)writeData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag;
  
  /**
   * Returns progress of current read or write, from 0.0 to 1.0, or NaN if no read/write (use isnan() to check).
   * "tag", "done" and "total" will be filled in if they aren't NULL.
   **/
  - (float)progressOfReadReturningTag:(long *)tag bytesDone:(NSUInteger *)done total:(NSUInteger *)total;
  - (float)progressOfWriteReturningTag:(long *)tag bytesDone:(NSUInteger *)done total:(NSUInteger *)total;
  
  /**
   * Secures the connection using SSL/TLS.
   *
   * This method may be called at any time, and the TLS handshake will occur after all pending reads and writes
   * are finished. This allows one the option of sending a protocol dependent StartTLS message, and queuing
   * the upgrade to TLS at the same time, without having to wait for the write to finish.
   * Any reads or writes scheduled after this method is called will occur over the secured connection.
   *
   * The possible keys and values for the TLS settings are well documented.
   * Some possible keys are:
   * - kCFStreamSSLLevel
   * - kCFStreamSSLAllowsExpiredCertificates
   * - kCFStreamSSLAllowsExpiredRoots
   * - kCFStreamSSLAllowsAnyRoot
   * - kCFStreamSSLValidatesCertificateChain
   * - kCFStreamSSLPeerName
   * - kCFStreamSSLCertificates
   * - kCFStreamSSLIsServer
   *
   * Please refer to Apple's documentation for associated values, as well as other possible keys.
   *
   * If you pass in nil or an empty dictionary, the default settings will be used.
   *
   * The default settings will check to make sure the remote party's certificate is signed by a
   * trusted 3rd party certificate agency (e.g. verisign) and that the certificate is not expired.
   * However it will not verify the name on the certificate unless you
   * give it a name to verify against via the kCFStreamSSLPeerName key.
   * The security implications of this are important to understand.
   * Imagine you are attempting to create a secure connection to MySecureServer.com,
   * but your socket gets directed to MaliciousServer.com because of a hacked DNS server.
   * If you simply use the default settings, and MaliciousServer.com has a valid certificate,
   * the default settings will not detect any problems since the certificate is valid.
   * To properly secure your connection in this particular scenario you
   * should set the kCFStreamSSLPeerName property to "MySecureServer.com".
   * If you do not know the peer name of the remote host in advance (for example, you're not sure
   * if it will be "domain.com" or "www.domain.com"), then you can use the default settings to validate the
   * certificate, and then use the X509Certificate class to verify the issuer after the socket has been secured.
   * The X509Certificate class is part of the CocoaAsyncSocket open source project.
   **/
  - (void)startTLS:(NSDictionary *)tlsSettings;
  
  /**
   * For handling readDataToData requests, data is necessarily read from the socket in small increments.
   * The performance can be much improved by allowing AsyncSocket to read larger chunks at a time and
   * store any overflow in a small internal buffer.
   * This is termed pre-buffering, as some data may be read for you before you ask for it.
   * If you use readDataToData a lot, enabling pre-buffering will result in better performance, especially on the iPhone.
   *
   * The default pre-buffering state is controlled by the DEFAULT_PREBUFFERING definition.
   * It is highly recommended one leave this set to YES.
   *
   * This method exists in case pre-buffering needs to be disabled by default for some unforeseen reason.
   * In that case, this method exists to allow one to easily enable pre-buffering when ready.
   **/
  - (void)enablePreBuffering;
  
  /**
   * When you create an AsyncSocket, it is added to the runloop of the current thread.
   * So for manually created sockets, it is easiest to simply create the socket on the thread you intend to use it.
   *
   * If a new socket is accepted, the delegate method onSocket:wantsRunLoopForNewSocket: is called to
   * allow you to place the socket on a separate thread. This works best in conjunction with a thread pool design.
   *
   * If, however, you need to move the socket to a separate thread at a later time, this
   * method may be used to accomplish the task.
   *
   * This method must be called from the thread/runloop the socket is currently running on.
   *
   * Note: After calling this method, all further method calls to this object should be done from the given runloop.
   * Also, all delegate calls will be sent on the given runloop.
   **/
  - (BOOL)moveToRunLoop:(NSRunLoop *)runLoop;
  
  /**
   * Allows you to configure which run loop modes the socket uses.
   * The default set of run loop modes is NSDefaultRunLoopMode.
   *
   * If you'd like your socket to continue operation during other modes, you may want to add modes such as
   * NSModalPanelRunLoopMode or NSEventTrackingRunLoopMode. Or you may simply want to use NSRunLoopCommonModes.
   *
   * Accepted sockets will automatically inherit the same run loop modes as the listening socket.
   *
   * Note: NSRunLoopCommonModes is defined in 10.5. For previous versions one can use kCFRunLoopCommonModes.
   **/
  - (BOOL)setRunLoopModes:(NSArray *)runLoopModes;
  - (BOOL)addRunLoopMode:(NSString *)runLoopMode;
  - (BOOL)removeRunLoopMode:(NSString *)runLoopMode;
  
  /**
   * Returns the current run loop modes the AsyncSocket instance is operating in.
   * The default set of run loop modes is NSDefaultRunLoopMode.
   **/
  - (NSArray *)runLoopModes;
  
  /**
   * In the event of an error, this method may be called during onSocket:willDisconnectWithError: to read
   * any data that's left on the socket.
   **/
  - (NSData *)unreadData;
  
  /* A few common line separators, for use with the readDataToData:... methods. */
  + (NSData *)CRLFData;   // 0x0D0A
  + (NSData *)CRData;     // 0x0D
  + (NSData *)LFData;     // 0x0A
  + (NSData *)ZeroData;   // 0x00
  
  @end
  