extension: split out an async specific broker for "after" events (#346)

Signed-off-by: James Hillyerd <james@hillyerd.com>

pkg/extension/broker.go

@@ -1,9 +1,7 @@
 package extension
 
 import (
-	"errors"
 	"sync"
-	"time"
 )
 
 // EventBroker maintains a list of listeners interested in a specific type
@@ -59,38 +57,3 @@ func (eb *EventBroker[E, R]) lockedRemoveListener(name string) {
 		}
 	}
 }
-
-// AsyncTestListener returns a func that will wait for an event and return it, or timeout
-// with an error.
-func (eb *EventBroker[E, R]) AsyncTestListener(capacity int) func() (*E, error) {
-	const name = "asyncTestListener"
-
-	// Send event down channel.
-	events := make(chan E, capacity)
-	eb.AddListener(name,
-		func(msg E) *R {
-			events <- msg
-			return nil
-		})
-
-	count := 0
-
-	return func() (*E, error) {
-		count++
-
-		defer func() {
-			if count >= capacity {
-				eb.RemoveListener(name)
-				close(events)
-			}
-		}()
-
-		select {
-		case event := <-events:
-			return &event, nil
-
-		case <-time.After(time.Second * 2):
-			return nil, errors.New("Timeout waiting for event")
-		}
-	}
-}