We don't need sync.Once, we can just select

client/rpc_client.go

@@ -75,11 +75,9 @@ func (r *rpcClient) call(ctx context.Context, address string, req Request, resp
 		return errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
 
-	var once sync.Once
 	stream := &rpcStream{
 		context: ctx,
 		request: req,
-		once:    once,
 		closed:  make(chan bool),
 		codec:   newRpcPlusCodec(msg, c, cf),
 	}
@@ -139,11 +137,9 @@ func (r *rpcClient) stream(ctx context.Context, address string, req Request, opt
 		return nil, errors.InternalServerError("go.micro.client", fmt.Sprintf("Error sending request: %v", err))
 	}
 
-	var once sync.Once
 	stream := &rpcStream{
 		context: ctx,
 		request: req,
-		once:    once,
 		closed:  make(chan bool),
 		codec:   newRpcPlusCodec(msg, c, cf),
 	}

client/rpc_stream.go

@@ -12,7 +12,6 @@ import (
 type rpcStream struct {
 	sync.RWMutex
 	seq     uint64
-	once    sync.Once
 	closed  chan bool
 	err     error
 	request Request
@@ -22,13 +21,11 @@ type rpcStream struct {
 
 func (r *rpcStream) isClosed() bool {
 	select {
-	case _, ok := <-r.closed:
-		if !ok {
-			return true
-		}
+	case <-r.closed:
+		return true
 	default:
+		return false
 	}
-	return false
 }
 
 func (r *rpcStream) Context() context.Context {
@@ -112,8 +109,11 @@ func (r *rpcStream) Error() error {
 }
 
 func (r *rpcStream) Close() error {
-	r.once.Do(func() {
+	select {
+	case <-r.closed:
+		return nil
+	default:
 		close(r.closed)
-	})
-	return r.codec.Close()
+		return r.codec.Close()
+	}
 }