Function gio_sys::g_buffered_input_stream_fill_async

pub unsafe extern fn g_buffered_input_stream_fill_async(stream: *mut GBufferedInputStream,
                                                        count: ssize_t,
                                                        io_priority: c_int,
                                                        cancellable: *mut GCancellable,
                                                        callback: GAsyncReadyCallback,
                                                        user_data: gpointer)