message: [tstring] Add `Hash64(const tstring&)` overload to prevent inadvertent temporary std::string creations.
  Also added `Hash64(const char*)` to avoid ambiguous overload resolution.
diff: @@ -36,10 +36,18 @@ inline uint64 Hash64(const char* data, size_t n) {
  return Hash64(data, n, 0xDECAFCAFFE);
  }
  +inline uint64 Hash64(const char* data) { return Hash64(data, ::strlen(data)); }
  +
  inline uint64 Hash64(const string& str) {
  return Hash64(str.data(), str.size());
  }
  +#ifdef USE_TSTRING
  +inline uint64 Hash64(const tstring& str) {
  + return Hash64(str.data(), str.size());
  +}
  +#endif // USE_TSTRING
  +
  inline uint64 Hash64Combine(uint64 a, uint64 b) {
  return a ^ (b + 0x9e3779b97f4a7800ULL + (a << 10) + (a >> 4));
  }
  