rework throttle

reuse throttle mechanism for catching global keys

Azaion.Annotator/Extensions/ThrottleExtensions.cs

@@ -0,0 +1,16 @@
+namespace Azaion.Annotator.Extensions;
+
+public static class ThrottleExt
+{
+    private static bool _throttleOn;
+    public static async Task Throttle(Func<Task> func, TimeSpan? throttleTime = null)
+    {
+        if (_throttleOn)
+            return;
+
+        _throttleOn = true;
+        await func();
+        await Task.Delay(throttleTime ?? TimeSpan.FromMilliseconds(500));
+        _throttleOn = false;
+    }
+}