message: fix potential issue withing 0-length strings
diff: @@ -144,6 +144,8 @@ uint32_t Serialize::implDirectorySize(std::string e) {
  }
  void Serialize::writeBytes(const void* buf, size_t sz) {
  + if(sz==0)
  + return;
  size_t at = entryBuf.size();
  entryBuf.resize(entryBuf.size()+sz);
  std::memcpy(&entryBuf[at],buf,sz);
  