text: var Stream = require('stream').Stream
  
  module.exports = legacy
  
  function legacy(fs) {
      return {
          ReadStream: ReadStream,
          WriteStream: WriteStream
      }
  
      function ReadStream(path, options) {
          if (!(this instanceof ReadStream)) return new ReadStream(path, options);
  
          Stream.call(this);
  
          var self = this;
  
          this.path = path;
          this.fd = null;
          this.readable = true;
          this.paused = false;
  
          this.flags = 'r';
          this.mode = 438;
          /*=0666*/
          this.bufferSize = 64 * 1024;
  
          options = options || {};
  
          // Mixin options into this
          var keys = Object.keys(options);
          for (var index = 0, length = keys.length; index < length; index++) {
              var key = keys[index];
              this[key] = options[key];
          }
  
          if (this.encoding) this.setEncoding(this.encoding);
  
          if (this.start !== undefined) {
              if ('number' !== typeof this.start) {
                  throw TypeError('start must be a Number');
              }
              if (this.end === undefined) {
                  this.end = Infinity;
              } else if ('number' !== typeof this.end) {
                  throw TypeError('end must be a Number');
              }
  
              if (this.start > this.end) {
                  throw new Error('start must be <= end');
              }
  
              this.pos = this.start;
          }
  
          if (this.fd !== null) {
              process.nextTick(function () {
                  self._read();
              });
              return;
          }
  
          fs.open(this.path, this.flags, this.mode, function (err, fd) {
              if (err) {
                  self.emit('error', err);
                  self.readable = false;
                  return;
              }
  
              self.fd = fd;
              self.emit('open', fd);
              self._read();
          })
      }
  
      function WriteStream(path, options) {
          if (!(this instanceof WriteStream)) return new WriteStream(path, options);
  
          Stream.call(this);
  
          this.path = path;
          this.fd = null;
          this.writable = true;
  
          this.flags = 'w';
          this.encoding = 'binary';
          this.mode = 438;
          /*=0666*/
          this.bytesWritten = 0;
  
          options = options || {};
  
          // Mixin options into this
          var keys = Object.keys(options);
          for (var index = 0, length = keys.length; index < length; index++) {
              var key = keys[index];
              this[key] = options[key];
          }
  
          if (this.start !== undefined) {
              if ('number' !== typeof this.start) {
                  throw TypeError('start must be a Number');
              }
              if (this.start < 0) {
                  throw new Error('start must be >= zero');
              }
  
              this.pos = this.start;
          }
  
          this.busy = false;
          this._queue = [];
  
          if (this.fd === null) {
              this._open = fs.open;
              this._queue.push([this._open, this.path, this.flags, this.mode, undefined]);
              this.flush();
          }
      }
  }
  