rem: SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count); writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);
add: mplex_write(fd, 0, io_buffer, io_buffer_count);
context: void io_flush(void){	int fd = multiplex_out_fd;	if (!io_buffer_count || no_flush) return;	if (io_multiplexing_out) {		SIVAL(io_buffer-4, 0, (MPLEX_BASE<<24) + io_buffer_count);		writefd_unbuffered(fd, io_buffer-4, io_buffer_count+4);	} else {		writefd_unbuffered(fd, io_buffer, io_buffer_count);	}	io_buffer_count = 0;}