client:fix ttrpc send hang

Signed-off-by: ningmingxiao <[email protected]>

client.go

@@ -535,10 +535,14 @@ func (c *Client) dispatch(ctx context.Context, req *Request, resp *Response) err
 		return err
 	}
 
-	s, err := c.createStream(0, p)
-	if err != nil {
-		return err
-	}
+	var s *stream
+	ch := make(chan error)
+	go func() {
+		s, err = c.createStream(0, p)
+		if err != nil {
+			ch <- err
+		}
+	}()
 	defer c.deleteStream(s)
 
 	var msg *streamMessage
@@ -547,6 +551,8 @@ func (c *Client) dispatch(ctx context.Context, req *Request, resp *Response) err
 		return ctx.Err()
 	case <-c.ctx.Done():
 		return ErrClosed
+	case err := <-ch:
+		return err
 	case <-s.recvClose:
 		// If recv has a pending message, process that first
 		select {