Attempts to write up to @count bytes from @buffer to @stream, as
with g_output_stream_write(). If @stream is not currently writable,
this will immediately return %G_IO_ERROR_WOULD_BLOCK, and you can
use g_pollable_output_stream_create_source() to create a #GSource
that will be triggered when @stream is writable.
Note that since this method never blocks, you cannot actually
use @cancellable to cancel it. However, it will return an error
if @cancellable has already been cancelled when you call, which
may happen if you call this method after a source triggers due
to having been cancelled.
Attempts to write up to @count bytes from @buffer to @stream, as with g_output_stream_write(). If @stream is not currently writable, this will immediately return %G_IO_ERROR_WOULD_BLOCK, and you can use g_pollable_output_stream_create_source() to create a #GSource that will be triggered when @stream is writable.
Note that since this method never blocks, you cannot actually use @cancellable to cancel it. However, it will return an error if @cancellable has already been cancelled when you call, which may happen if you call this method after a source triggers due to having been cancelled.