Make mk2ser wait for goroutine to finish on Close.

mk2if/mk2.go

@@ -25,6 +25,7 @@ type mk2Ser struct {
 	locked bool
 	sync.RWMutex
 	infochan chan *Mk2Info
+	wg sync.WaitGroup
 }
 
 func NewMk2Connection(dev io.ReadWriter) (Mk2If, error) {
@@ -38,6 +39,7 @@ func NewMk2Connection(dev io.ReadWriter) (Mk2If, error) {
 	mk2.setTarget()
 	mk2.run = make(chan struct{})
 	mk2.infochan = make(chan *Mk2Info)
+	mk2.wg.Add(1)
 	go mk2.frameLock()
 	return mk2, nil
 }
@@ -50,8 +52,10 @@ func (mk2 *mk2Ser) frameLock() {
 	for {
 		select {
 		case <-mk2.run:
-			break
+			mk2.wg.Done()
+			return
 		default:
+		}
 		if mk2.locked {
 			size = mk2.readByte()
 			l, err := io.ReadFull(mk2.p, frame[0:int(size)+1])
@@ -83,12 +87,12 @@ func (mk2 *mk2Ser) frameLock() {
 			size = tmp
 		}
 	}
-	}
 }
 
 // Close Mk2
 func (mk2 *mk2Ser) Close() {
 	close(mk2.run)
+	mk2.wg.Wait()
 }
 
 // Returns last known state with all reported errors since previous poll.