private void initFields() {
      messageType_ = main.Messages.Message.MessageType.ExecutionStarting;
      messageId_ = 0L;
      executionStartingRequest_ = main.Messages.ExecutionStartingRequest.getDefaultInstance();
      specExecutionStartingRequest_ = main.Messages.SpecExecutionStartingRequest.getDefaultInstance();
      specExecutionEndingRequest_ = main.Messages.SpecExecutionEndingRequest.getDefaultInstance();
      scenarioExecutionStartingRequest_ = main.Messages.ScenarioExecutionStartingRequest.getDefaultInstance();
      scenarioExecutionEndingRequest_ = main.Messages.ScenarioExecutionEndingRequest.getDefaultInstance();
      executeStepRequest_ = main.Messages.ExecuteStepRequest.getDefaultInstance();
      executeStepResponse_ = main.Messages.ExecuteStepResponse.getDefaultInstance();
      executionEndingRequest_ = main.Messages.ExecutionEndingRequest.getDefaultInstance();
      stepValidateRequest_ = main.Messages.StepValidateRequest.getDefaultInstance();
      stepValidateResponse_ = main.Messages.StepValidateResponse.getDefaultInstance();
      executionStatusResponse_ = main.Messages.ExecutionStatusResponse.getDefaultInstance();
    }