The default implementation of can_poll always returns %TRUE.
The default implementation of read_nonblocking calls
g_pollable_input_stream_is_readable(), and then calls
g_input_stream_read() if it returns %TRUE. This means you only need
to override it if it is possible that your is_readable
implementation may return %TRUE when the stream is not actually
readable.
The interface for pollable input streams.
The default implementation of
can_pollalways returns %TRUE.The default implementation of
read_nonblockingcalls g_pollable_input_stream_is_readable(), and then calls g_input_stream_read() if it returns %TRUE. This means you only need to override it if it is possible that youris_readableimplementation may return %TRUE when the stream is not actually readable.