code: @Override
      public StartAssociationsOnceResult startAssociationsOnce(StartAssociationsOnceRequest request) {
          request = beforeClientExecution(request);
          return executeStartAssociationsOnce(request);
      }
docs: <p>
  Use this API action to run an association immediately and only one time. This action can be helpful when
  troubleshooting associations.
  </p>
  
  @param startAssociationsOnceRequest
  @return Result of the StartAssociationsOnce operation returned by the service.
  @throws InvalidAssociationException
  The association is not valid or does not exist.
  @throws AssociationDoesNotExistException
  The specified association does not exist.
  @sample AWSSimpleSystemsManagement.StartAssociationsOnce
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/ssm-2014-11-06/StartAssociationsOnce" target="_top">AWS API
  Documentation</a>