Fix deadlock when deleting actors

environment.go

@@ -137,11 +137,13 @@ func (this *environment) Del(ctx context.Context, actors ...Actor) error {
 	channels := []<- chan struct { } { }
 	for _, actor := range actors {
 		info := this.info(actor)
-		if info.done != nil {
+		if info.stopped != nil {
 			channels = append(channels, info.stopped)
 		}
+		info.done()
 	}
 	for _, channel := range channels {
+		if channel == nil { continue }
 		select {
 		case <- channel:
 		case <- ctx.Done():
@@ -250,7 +252,11 @@ func (this *environment) run(actor Actor) {
 	// contains context information
 	info := this.info(actor)
 	ctx := info.ctx
-	defer close(info.stopped)
+	defer func() {
+		if info.stopped != nil {
+			close(info.stopped)
+		}
+	}()
 	
 	switch actor := actor.(type) {
 	case Runnable: