code: @Override
      public UnsubscribeResult unsubscribe(UnsubscribeRequest request) {
          request = beforeClientExecution(request);
          return executeUnsubscribe(request);
      }
docs: <p>
  Deletes a subscription. If the subscription requires authentication for deletion, only the owner of the
  subscription or the topic's owner can unsubscribe, and an AWS signature is required. If the
  <code>Unsubscribe</code> call does not require authentication and the requester is not the subscription owner, a
  final cancellation message is delivered to the endpoint, so that the endpoint owner can easily resubscribe to the
  topic if the <code>Unsubscribe</code> request was unintended.
  </p>
  <p>
  This action is throttled at 100 transactions per second (TPS).
  </p>
  
  @param unsubscribeRequest
  Input for Unsubscribe action.
  @return Result of the Unsubscribe 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.
  @throws NotFoundException
  Indicates that the requested resource does not exist.
  @throws InvalidSecurityException
  The credential signature isn't valid. You must use an HTTPS endpoint and sign your request using
  Signature Version 4.
  @sample AmazonSNS.Unsubscribe
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/sns-2010-03-31/Unsubscribe" target="_top">AWS API
  Documentation</a>