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),
 	}