Shared/Metric: Fix crash on shutdown

Fix crash on shutdown with metrics enabled but InfluxDB stopping before worldserver

src/common/Metric/Metric.cpp

@@ -208,16 +208,17 @@ void Metric::ScheduleSend()
     }
 }
 
-void Metric::ForceSend()
+void Metric::Unload()
 {
     // Send what's queued only if io_service is stopped (so only on shutdown)
     if (_enabled && _batchTimer->get_io_service().stopped())
     {
         _enabled = false;
         SendBatch();
-        _batchTimer->cancel();
-        _overallStatusTimer->cancel();
     }
+
+    _batchTimer->cancel();
+    _overallStatusTimer->cancel();
 }
 
 void Metric::ScheduleOverallStatusLog()

src/common/Metric/Metric.h

@@ -110,7 +110,7 @@ public:
 
     void LogEvent(std::string const& category, std::string const& title, std::string const& description);
 
-    void ForceSend();
+    void Unload();
     bool IsEnabled() const { return _enabled; }
 };
 

src/server/worldserver/Main.cpp

@@ -232,7 +232,7 @@ extern int main(int argc, char** argv)
     std::shared_ptr<void> sMetricHandle(nullptr, [](void*)
     {
         TC_METRIC_EVENT("events", "Worldserver shutdown", "");
-        sMetric->ForceSend();
+        sMetric->Unload();
     });
 
     sScriptMgr->SetScriptLoader(AddScripts);