Fired when data (complete lines) come in through stderr.
The 'callback' is called when the 'Stderr' event is emited.
The argument 'e' has the following properties:
e.text (buffer) e.EOL
The Stderr event is fired every time the process on the remote host outputs a line in its error output. The incoming data is provided through the Text parameter.
When the error stream is closed by the server, a string containing only one NULL character is delivered through this event.