@Override
    public ByteBuffer write(@NotNull ByteBuffer buffer) throws IOException {
      putHeader(buffer, /* deleted: */ false);
      keyWriter.write(buffer.position(HEADER_SIZE).limit(HEADER_SIZE + keySize));
      valueWriter.write(buffer.position(HEADER_SIZE + keySize).limit(HEADER_SIZE + keySize + valueSize));
      return buffer;
    }
@Override
    public ByteBuffer write(@NotNull ByteBuffer buffer)