code: @Override
      public UpdateChapCredentialsResult updateChapCredentials(UpdateChapCredentialsRequest request) {
          request = beforeClientExecution(request);
          return executeUpdateChapCredentials(request);
      }
docs: <p>
  Updates the Challenge-Handshake Authentication Protocol (CHAP) credentials for a specified iSCSI target. By
  default, a gateway does not have CHAP enabled; however, for added security, you might use it.
  </p>
  <important>
  <p>
  When you update CHAP credentials, all existing connections on the target are closed and initiators must reconnect
  with the new credentials.
  </p>
  </important>
  
  @param updateChapCredentialsRequest
  A JSON object containing one or more of the following fields:</p>
  <ul>
  <li>
  <p>
  <a>UpdateChapCredentialsInput$InitiatorName</a>
  </p>
  </li>
  <li>
  <p>
  <a>UpdateChapCredentialsInput$SecretToAuthenticateInitiator</a>
  </p>
  </li>
  <li>
  <p>
  <a>UpdateChapCredentialsInput$SecretToAuthenticateTarget</a>
  </p>
  </li>
  <li>
  <p>
  <a>UpdateChapCredentialsInput$TargetARN</a>
  </p>
  </li>
  @return Result of the UpdateChapCredentials operation returned by the service.
  @throws InvalidGatewayRequestException
  An exception occurred because an invalid gateway request was issued to the service. For more information,
  see the error and message fields.
  @throws InternalServerErrorException
  An internal server error has occurred during the request. For more information, see the error and message
  fields.
  @sample AWSStorageGateway.UpdateChapCredentials
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/storagegateway-2013-06-30/UpdateChapCredentials"
  target="_top">AWS API Documentation</a>