A basic event debouncer for .NET, similar to http://underscorejs.org/#debounce

Events.cs

using System;
using System.Collections.Generic;
using System.Timers;

public static class Events {
    static Dictionary<EventHandler, Timer> _debounceTimers;
    
    public static EventHandler Debounce(TimeSpan interval, Action<object, EventArgs> action, ISynchronizeInvoke synchronizingObject = null) {
        object lastSender = null;
        EventArgs lastArgs = null;
        
        var timer = new Timer();
        if (_debounceTimers == null)
            _debounceTimers = new Dictionary<EventHandler, Timer>();
        
        timer.Interval = interval.TotalMilliseconds;
        timer.SynchronizingObject = synchronizingObject;
        timer.Elapsed += (sender, args) => {
            timer.Enabled = false;
            timer.Stop();
            
            action(lastSender, lastArgs);
        };
        
        EventHandler handler = (sender, args) => {
            lastSender = sender;
            lastArgs = args;
            
            timer.Stop();
            timer.Start();
            timer.Enabled = true;
        };
        
        _debounceTimers.Add(handler, timer);
        
        return handler;
    }
    
    public static void DisposeDebouncers(this EventHandler handler) {
        handler.ThrowIfNull("handler");
        
        if (_debounceTimers.ContainsKey(handler)) {
            var timer = _debounceTimers[handler];
            if (timer != null) {
                timer.Stop();
                timer.Enabled = false;
                timer.Dispose();
            }
        }
    }
}

EventsTest.cs

public class EventExtensionsTest {
    event EventHandler FrequentEvent;

    [Fact]
    void DebounceTest() {
        var counter = 0;
        var span = TimeSpan.FromSeconds(1);
        var handler = EventExtensions.Debounce(span, (sender, e) => counter++);
        FrequentEvent += handler;

        FrequentEvent(this, null);
        FrequentEvent(this, null);
        FrequentEvent(this, null);

        Thread.Sleep(2000);
        Assert.Equal(1, counter);

        FrequentEvent(this, null);
        FrequentEvent(this, null);
        FrequentEvent(this, null);
        FrequentEvent(this, null);
        FrequentEvent(this, null);

        Thread.Sleep(2000);
        Assert.Equal(2, counter);

        FrequentEvent.DisposeDebouncers();
        FrequentEvent -= handler;
    }
}

This is not thread safe. At least _debounceTimers dictionary must be ConcurrentDictionary instead