Add timing class from TMV

KeepersCompound.Lightmapper/Timing.cs

@@ -0,0 +1,47 @@
+using System.Diagnostics;
+
+namespace KeepersCompound.Lightmapper;
+
+public static class Timing
+{
+    static readonly Dictionary<string, TimeSpan> _stages = new();
+
+    public static void Reset()
+    {
+        _stages.Clear();
+    }
+
+    public static void TimeStage(string stagename, Action action)
+    {
+        var watch = Stopwatch.StartNew();
+        action();
+        watch.Stop();
+        AddOrIncrement(stagename, watch.Elapsed);
+    }
+
+    public static T TimeStage<T>(string stagename, Func<T> action)
+    {
+        var watch = Stopwatch.StartNew();
+        var value = action();
+        watch.Stop();
+        AddOrIncrement(stagename, watch.Elapsed);
+        return value;
+    }
+
+    public static void LogAll()
+    {
+        foreach (var (stagename, time) in _stages)
+        {
+            Console.WriteLine($"[{stagename}]: {time:g}");
+        }
+    }
+
+    private static void AddOrIncrement(string stagename, TimeSpan elapsed)
+    {
+        if (_stages.TryGetValue(stagename, out var time))
+        {
+            elapsed += time;
+        }
+        _stages[stagename] = elapsed;
+    }
+}