Fix: CBenchmark.Begin() with CBenchmark.End() throws an exception

VocaluxeLib/Log/CBenchmark.cs

@@ -64,7 +64,7 @@ namespace VocaluxeLib.Log
         public void Stop(bool success = true)
         {
             if (_Watch == null)
-                throw new InvalidOperationException("Timer is not running.");
+                return;
             _Watch.Stop();
             double duration = _GetElapsedTime(_Watch);