Occurs when data can be written to the socket.
The OnWrite event occurs when the application can write data to the server. This event will typically occur when a connection is first established with the remote host, and after the Write method has failed because there was insufficient memory available in the socket send buffers. In the second case, when some of the buffered data has been successfully sent to the remote host and there is space available in the send buffers, this event is used to signal the application that it may attempt to send more data.
This event is only generated if the client is in non-blocking mode.