Function pomp_ctx_set_send_cb 

pub unsafe extern "C" fn pomp_ctx_set_send_cb(
    ctx: *mut pomp_ctx,
    cb: pomp_send_cb_t,
) -> c_int

Set the function to call when send operations are completed. This allows application to be notified of actual completion in case operations are internally queued. @param ctx : context. @param cb : function to call when send operations are completed. The userdata argument will be the same as the one set when creating the context. @return 0 in case of success, negative errno value in case of error.