using different chans to handle event/heartbeat

Signed-off-by: Wei Liu <liuweixa@redhat.com>

Author: skeeey

pkg/cloudevents/server/grpc/broker.go

@@ -184,6 +184,8 @@ func (bkr *GRPCBroker) Subscribe(subReq *pbv1.SubscriptionRequest, subServer pbv
 			case evt := <-heartbeatCh:
 				if err := subServer.Send(evt); err != nil {
 					klog.Errorf("failed to send heartbeat: %v", err)
+					// Unblock producers (handler select) and exit heartbeat ticker.
+					cancel()
 					select {
 					case sendErrCh <- err:
 					default:
@@ -193,6 +195,8 @@ func (bkr *GRPCBroker) Subscribe(subReq *pbv1.SubscriptionRequest, subServer pbv
 			case evt := <-eventCh:
 				if err := subServer.Send(evt); err != nil {
 					klog.Errorf("failed to send event: %v", err)
+					// Unblock producers (handler select) and exit heartbeat ticker.
+					cancel()
 					select {
 					case sendErrCh <- err:
 					default: