iob_bytesleft - Man Page
how many bytes are still to be sent?
Syntax
#include <iob.h>
uint64 iob_bytesleft(const io_batch* b);
Description
iob_bytesleft returns the number of bytes that still need to be sent in this IO batch. If you just want to see whether you need to call iob_send again, there is no advantage in this function to calling iob_send directly and looking whether it returned 0.