create_source

Creates a SocketSource that triggers when this can be written, or cancellable is triggered or an error occurs.

The callback on the source is of the PollableSourceFunc type.

As with is_writable, it is possible that the stream may not actually be writable even after the source triggers, so you should use write_nonblocking rather than write from the callback.

The behaviour of this method is undefined if can_poll returns false for this.

Parameters:

this	a PollableOutputStream.
cancellable	a Cancellable, or null

Returns:

a new SocketSource