Method decompress

src/test/compressor/compressor_example.h:42–46

  }

  int decompress(const bufferlist &in, bufferlist &out, std::optional<int32_t> compressor_message) override
  {
    out = in;
    return 0;
  }
  int decompress(bufferlist::const_iterator &p, size_t compressed_len, bufferlist &out, std::optional<int32_t> compressor_message) override
  {
    p.copy(std::min<size_t>(p.get_remaining(), compressed_len), out);