code: @Override
      public GetExecutionHistoryResult getExecutionHistory(GetExecutionHistoryRequest request) {
          request = beforeClientExecution(request);
          return executeGetExecutionHistory(request);
      }
docs: <p>
  Returns the history of the specified execution as a list of events. By default, the results are returned in
  ascending order of the <code>timeStamp</code> of the events. Use the <code>reverseOrder</code> parameter to get
  the latest events first.
  </p>
  <p>
  If <code>nextToken</code> is returned, there are more results available. The value of <code>nextToken</code> is a
  unique pagination token for each page. Make the call again using the returned token to retrieve the next page.
  Keep all other arguments unchanged. Each pagination token expires after 24 hours. Using an expired pagination
  token will return an <i>HTTP 400 InvalidToken</i> error.
  </p>
  
  @param getExecutionHistoryRequest
  @return Result of the GetExecutionHistory operation returned by the service.
  @throws ExecutionDoesNotExistException
  The specified execution does not exist.
  @throws InvalidArnException
  The provided Amazon Resource Name (ARN) is invalid.
  @throws InvalidTokenException
  The provided token is invalid.
  @sample AWSStepFunctions.GetExecutionHistory
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/states-2016-11-23/GetExecutionHistory" target="_top">AWS API
  Documentation</a>