code: private OperationResult getOperationResult() {
          if (operationResult == null) {
              this.operationResult = (OperationResult) marshaller.unmarshal(new StringSource(getPayload(String.class)));
          }
  
          return operationResult;
      }
docs: Gets the operation result if any or tries to unmarshal String payload representation to an operation result model.
  @return