Timing for Razor rendering

TraceScope.cs

namespace Timing
{
    using System;
    using System.Diagnostics;
    using System.Web.Mvc;

    public class TraceScope : IDisposable
    {
        private readonly string _name;
        private readonly ViewContext _viewContext;
        private readonly Stopwatch _stopwatch;

        public TraceScope(string name, ViewContext viewContext)
        {
            _name = name;
            _viewContext = viewContext;
            _stopwatch = Stopwatch.StartNew();
        }

        public void Dispose()
        {
            _stopwatch.Stop();
            _viewContext.Writer.Write("<!-- {0} rendered in {1} milliseconds -->", _name, _stopwatch.ElapsedMilliseconds);
        }
    }

    public static class HtmlHelperExtensions
    {
        public static IDisposable BeginTrace(this HtmlHelper helper, string name)
        {
            return new TraceScope(name, helper.ViewContext);
        }
    }
}