add comment to clarify ack_delay use
@@ -3317,7 +3317,8 @@ static int handle_ack_frame(quicly_conn_t *conn, size_t epoch, quicly_ack_frame_
LOG_CONNECTION_EVENT(conn, QUICLY_EVENT_TYPE_QUICTRACE_RECV_ACK, INT_EVENT_ATTR(ACK_DELAY, frame->ack_delay));
- /* update loss detection engine on ack */
+ /* Update loss detection engine on ack. The function uses ack_delay only when the largest_newly_acked is also the largest acked so far.
+ * So, it does not matter if the ack_delay being passed in does not apply to the largest_newly_acked. */
quicly_loss_on_ack_received(&conn->egress.loss, largest_newly_acked.packet_number, now, largest_newly_acked.sent_at,
frame->ack_delay, bytes_acked);
