docs: private <T> RequestBuilder doPrepareRequestBuilderImpl(
        ResponseReader responseReader, String methodName, RpcStatsContext statsContext,
        String requestData, AsyncCallback<T> callback) {
  
      if (getServiceEntryPoint() == null) {
        throw new NoServiceEntryPointSpecifiedException();
      }
  
      RequestCallback responseHandler = doCreateRequestCallback(responseReader,
          methodName, statsContext, callback);
  
      ensureRpcRequestBuilder();
  
      rpcRequestBuilder.create(getServiceEntryPoint());
      rpcRequestBuilder.setCallback(responseHandler);
      
      // changed code
      rpcRequestBuilder.setSync(isSync(methodName));
      // changed code
      
      rpcRequestBuilder.setContentType(RPC_CONTENT_TYPE);
      rpcRequestBuilder.setRequestData(requestData);
      rpcRequestBuilder.setRequestId(statsContext.getRequestId());
      return rpcRequestBuilder.finish();
    }