private com.google.protobuf.SingleFieldBuilder<
          main.Messages.ScenarioExecutionStartingRequest, main.Messages.ScenarioExecutionStartingRequest.Builder, main.Messages.ScenarioExecutionStartingRequestOrBuilder> 
          getScenarioExecutionStartingRequestFieldBuilder() {
        if (scenarioExecutionStartingRequestBuilder_ == null) {
          scenarioExecutionStartingRequestBuilder_ = new com.google.protobuf.SingleFieldBuilder<
              main.Messages.ScenarioExecutionStartingRequest, main.Messages.ScenarioExecutionStartingRequest.Builder, main.Messages.ScenarioExecutionStartingRequestOrBuilder>(
                  scenarioExecutionStartingRequest_,
                  getParentForChildren(),
                  isClean());
          scenarioExecutionStartingRequest_ = null;
        }
        return scenarioExecutionStartingRequestBuilder_;
      }