.

go/internal/xtracing/tracetest/tracetest.go

@@ -551,6 +551,16 @@ func (t *T) RxEvent(event interface{}) {
 	}
 	t.tracev = append(t.tracev, eventTrace{t0, stream, event})
 	ch := t.chanForStream(stream)
+
+	var delay time.Duration
+	d, ok := t.delayInjectTab[stream]
+	if ok {
+		if d.seqno == d.delayAt {
+			delay = d.delayT
+		}
+		d.seqno++
+	}
+
 	t.mu.Unlock()
 
 	if ch == nil {
@@ -583,9 +593,10 @@ func (t *T) RxEvent(event interface{}) {
 	// http://www.1024cores.net/home/relacy-race-detector
 	// http://www.1024cores.net/home/relacy-race-detector/rrd-introduction
 
+	if delay != 0 {
+		time.Sleep(delay)
+	}
 
-	// TODO timeout: deadlock? (print all-in-flight events on timeout)
-	// XXX  or better ^^^ to do on receiver side? -> yes - on receiver
 	ch.Send(event)
 }