code: @Override
    public ConvertManager converter()
    {
      if (_convertManager == null) {
        _convertManager = provider(Key.of(ConvertManager.class));
      }
  
      return _convertManager.get();
    }
docs: /*
  @Override
  public <S, T> Convert<S, T> converter(Class<S> source, Class<T> target)
  {
  if (_convertManager == null) {
  _convertManager = provider(Key.of(ConvertManager.class));
  }
  
  return _convertManager.get().converter(source, target);
  }