@Override
  public @NotNull Collection<K> read(@NotNull DataInput in) throws IOException {
    int size = DataInputOutputUtil.readINT(in);
    if (size == 0) {
      return Collections.emptyList();
    }
    if (size == 1) {
      return Collections.singletonList(myDataExternalizer.read(in));
    }
    List<K> list = new ArrayList<>(size);
    for (int idx = 0; idx < size; idx++) {
      list.add(myDataExternalizer.read(in));
    }
    return list;
  }
@Override
  public @NotNull Collection<K> read(@NotNull DataInput in)