Is ikcp_check really useful?

[jamboree]

The doc for ikcp_check says:

Determine when should you invoke ikcp_update

and in ikcp_check

kcp/ikcp.c

Line 1211 in f4f3a89

tm_flush = _itimediff(ts_flush, current);

kcp/ikcp.c

Line 1222 in f4f3a89

minimal = (IUINT32)(tm_packet < tm_flush ? tm_packet : tm_flush);

the return timepoint may be less than ts_flush.

However, in ikcp_update

kcp/ikcp.c

Line 1164 in f4f3a89

slap = _itimediff(kcp->current, kcp->ts_flush);

kcp/ikcp.c

Lines 1171 to 1177 in f4f3a89

	if (slap >= 0) {
	kcp->ts_flush += kcp->interval;
	if (_itimediff(kcp->current, kcp->ts_flush) >= 0) {
	kcp->ts_flush = kcp->current + kcp->interval;
	}
	ikcp_flush(kcp);
	}

ikcp_flush is called only if the current timepoint is greater or equal to ts_flush, which makes ikcp_check pointless.