code: public Observable<TextOperationResult> getTextOperationResultAsync(String operationId) {
          return getTextOperationResultWithServiceResponseAsync(operationId).map(new Func1<ServiceResponse<TextOperationResult>, TextOperationResult>() {
              @Override
              public TextOperationResult call(ServiceResponse<TextOperationResult> response) {
                  return response.body();
              }
          });
      }
docs: This interface is used for getting text operation result. The URL to this interface should be retrieved from 'Operation-Location' field returned from Recognize Text interface.
  
  @param operationId Id of the text operation returned in the response of the 'Recognize Text'
  @throws IllegalArgumentException thrown if parameters fail the validation
  @return the observable to the TextOperationResult object