code: @Override
      public ListSubscriptionsResult listSubscriptions(ListSubscriptionsRequest request) {
          request = beforeClientExecution(request);
          return executeListSubscriptions(request);
      }
docs: <p>
  Returns a list of the requester's subscriptions. Each call returns a limited list of subscriptions, up to 100. If
  there are more subscriptions, a <code>NextToken</code> is also returned. Use the <code>NextToken</code> parameter
  in a new <code>ListSubscriptions</code> call to get further results.
  </p>
  <p>
  This action is throttled at 30 transactions per second (TPS).
  </p>
  
  @param listSubscriptionsRequest
  Input for ListSubscriptions action.
  @return Result of the ListSubscriptions operation returned by the service.
  @throws InvalidParameterException
  Indicates that a request parameter does not comply with the associated constraints.
  @throws InternalErrorException
  Indicates an internal service error.
  @throws AuthorizationErrorException
  Indicates that the user has been denied access to the requested resource.
  @sample AmazonSNS.ListSubscriptions
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/sns-2010-03-31/ListSubscriptions" target="_top">AWS API
  Documentation</a>