Send the start of a data fragment stream to a websocket client.
          Subsequent data should be sent using sendFragment().
          A fragment stream is completed when sendFragmentEnd() is called.

          If data is a unicode object then the frame is sent as Text.
          If the data is a bytearray object then the frame is sent as Binary.

def sendFragmentStart(self, data):
      """
          Send the start of a data fragment stream to a websocket client.
          Subsequent data should be sent using sendFragment().
          A fragment stream is completed when sendFragmentEnd() is called.

          If data is a unicode object then the frame is sent as Text.
          If the data is a bytearray object then the frame is sent as Binary.
      """
      opcode = BINARY
      if isinstance(data, unicode):
         opcode = TEXT
      self._sendMessage(True, opcode, data)