code: protected final StorageException materializeException(final OperationContext opContext) {
          if (this.getException() != null) {
              return this.getException();
          }
  
          return StorageException.translateException(this, null, opContext);
      }
docs: Returns either the held exception from the operation if it is set, otherwise the translated exception.
  
  @param request
  the reference to the HttpURLConnection for the operation.
  @param opContext
  an object used to track the execution of the operation
  @return the exception to throw.