Enhance the event store interface to support channeling (#7343)

- Avoids code duplication across the other targets. By having a
  centralized function call.

- Reduce the room for race.

pkg/event/target/redis.go

@@ -69,8 +69,12 @@ func (target *RedisTarget) ID() event.TargetID {
 	return target.id
 }
 
-// Send - sends event to Redis.
-func (target *RedisTarget) Send(eventData event.Event) error {
+// Save - Sends event directly without persisting.
+func (target *RedisTarget) Save(eventData event.Event) error {
+	return target.send(eventData)
+}
+
+func (target *RedisTarget) send(eventData event.Event) error {
 	conn := target.pool.Get()
 	defer func() {
 		// FIXME: log returned error. ignore time being.
@@ -109,6 +113,11 @@ func (target *RedisTarget) Send(eventData event.Event) error {
 	return nil
 }
 
+// Send - interface compatible method does no-op.
+func (target *RedisTarget) Send(eventKey string) error {
+	return nil
+}
+
 // Close - does nothing and available for interface compatibility.
 func (target *RedisTarget) Close() error {
 	return nil