code: @Override
      public AddInstanceFleetResult addInstanceFleet(AddInstanceFleetRequest request) {
          request = beforeClientExecution(request);
          return executeAddInstanceFleet(request);
      }
docs: <p>
  Adds an instance fleet to a running cluster.
  </p>
  <note>
  <p>
  The instance fleet configuration is available only in Amazon EMR versions 4.8.0 and later, excluding 5.0.x.
  </p>
  </note>
  
  @param addInstanceFleetRequest
  @return Result of the AddInstanceFleet operation returned by the service.
  @throws InternalServerException
  This exception occurs when there is an internal failure in the EMR service.
  @throws InvalidRequestException
  This exception occurs when there is something wrong with user input.
  @sample AmazonElasticMapReduce.AddInstanceFleet
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/elasticmapreduce-2009-03-31/AddInstanceFleet"
  target="_top">AWS API Documentation</a>