code: public void propagateAsErrorIfCancelException(final Throwable t) {
      if ((t instanceof OperationCanceledError)) {
        throw ((OperationCanceledError)t);
      }
      final RuntimeException opCanceledException = this.getPlatformOperationCanceledException(t);
      if ((opCanceledException != null)) {
        throw new OperationCanceledError(opCanceledException);
      }
    }
docs: Rethrows OperationCanceledErrors and wraps platform specific OperationCanceledExceptions. Does nothing for any other type of Throwable.