pollable_stream_write

Tries to write to stream, as with write (if blocking is true) or write_nonblocking (if blocking is false).

This can be used to more easily share code between blocking and non-blocking implementations of a method.

If blocking is false, then stream must be a PollableOutputStream for which can_poll returns true or else the behavior is undefined. If blocking is true, then stream does not need to be a PollableOutputStream.

Parameters:

stream	a OutputStream.
buffer	the buffer containing the data to write.
blocking	whether to do blocking I/O
cancellable	optional Cancellable object, null to ignore.
count	the number of bytes to write

Returns:

the number of bytes written, or -1 on error.