message: core: fix warning
diff: @@ -29,7 +29,7 @@ private:
  struct Timeout {
  std::function<void()> callback{};
  dl_time_t time{};
  - double duration_s{0.0f};
  + double duration_s{0.0};
  };
  std::map<void *, std::shared_ptr<Timeout>> _timeouts{};
  