title: What are some reasons NetworkStream.Read would hang/block?
body: <p>MSDN documentation seems to suggest that NetworkStream.Read will always return immediately. If no data is found it returns 0. However, I have some code that is currently deployed, that only in some cases (and I haven't figured out which ones yet), NetworkStream.Read appears to hang. Here is the stack trace which i was able to gather from a dump file</p>
  
  <pre>
  00000000705ae850 000007fef784f60d DomainBoundILStubClass.IL_STUB(IntPtr, Byte*, Int32, System.Net.Sockets.SocketFlags)
  00000000705ae930 000007fef785c930 System.Net.Sockets.Socket.Receive(Byte[], Int32, Int32, System.Net.Sockets.SocketFlags, System.Net.Sockets.SocketError ByRef)
  00000000705ae9b0 000007ff004eb668 System.Net.Sockets.NetworkStream.Read(Byte[], Int32, Int32)
  00000000705aea40 000007fef784e6ae MySocketStuff.SocketConnectCallback(System.IAsyncResult)
  00000000705aeb20 000007fef84f2bbb System.Net.LazyAsyncResult.Complete(IntPtr)
  00000000705aeb90 000007fef7853c7b System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
  00000000705aebe0 000007fef784e5d3 System.Net.ContextAwareResult.Complete(IntPtr)
  00000000705aec40 000007fef7d027f9 System.Net.LazyAsyncResult.ProtectedInvokeCallback(System.Object, IntPtr)
  00000000705aeca0 000007fef8b9815e System.Net.Sockets.Socket.ConnectCallback()
  00000000705aed20 000007fef93e14c2 System.Threading._ThreadPoolWaitOrTimerCallback.PerformWaitOrTimerCallback(System.Object, Boolean)
  </pre>
  
  <p>I notice that the NetworkStrea.Read actually calls Socket.Receive which can be blocking as far as I understand. I just don't know why sometimes it would block and sometimes it would not.</p>