code: @Override
      public StartTriggerResult startTrigger(StartTriggerRequest request) {
          request = beforeClientExecution(request);
          return executeStartTrigger(request);
      }
docs: <p>
  Starts an existing trigger. See <a href="http://docs.aws.amazon.com/glue/latest/dg/trigger-job.html">Triggering
  Jobs</a> for information about how different types of trigger are started.
  </p>
  
  @param startTriggerRequest
  @return Result of the StartTrigger operation returned by the service.
  @throws InvalidInputException
  The input provided was not valid.
  @throws InternalServiceException
  An internal service error occurred.
  @throws EntityNotFoundException
  A specified entity does not exist
  @throws OperationTimeoutException
  The operation timed out.
  @throws ResourceNumberLimitExceededException
  A resource numerical limit was exceeded.
  @throws ConcurrentRunsExceededException
  Too many jobs are being run concurrently.
  @sample AWSGlue.StartTrigger
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/glue-2017-03-31/StartTrigger" target="_top">AWS API
  Documentation</a>