ensure entry is registered before timeout is armed.

In the case of a zero timeout, the AfterFunc would attempt to deregister an unregistered entry.
Then a zombie entry would be added that would never be deregistered.

publish.go

@@ -99,6 +99,12 @@ func (p *EventPublisher) Publish(eventID string, eventJSON []byte, timeout time.
 		result:    make(chan publishResult, 1),
 	}
 
+	p.mu.Lock()
+	p.pending[eventID] = entry
+	connected := p.envoy.IsConnected()
+
+	// use timeout if positive and nonzero
+	if timeout > time.Duration(0) {
 		entry.timer = time.AfterFunc(timeout, func() {
 			p.mu.Lock()
 			p.deregister(eventID)
@@ -107,10 +113,7 @@ func (p *EventPublisher) Publish(eventID string, eventJSON []byte, timeout time.
 				PublishTimeout{EventID: eventID, At: time.Now()})
 			p.deliver(entry, publishResult{err: errors.New("publish timeout")})
 		})
-
-	p.mu.Lock()
-	p.pending[eventID] = entry
-	connected := p.envoy.IsConnected()
+	}
 	p.mu.Unlock()
 
 	if connected {