One file (few lines) implement for performance check. for C# / .NET

Performance.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Web;

namespace Dev.Lib
{
    public static class Performance
    {

        public static T Check<T>(string name, Func<T> func, long expectedInMs = 500)
        {
            try
            {
                // Run the benchmark.
                Stopwatch watch = Stopwatch.StartNew();
                T result =  func.Invoke();
                watch.Stop();

                // Output results.
                var elapsedMilliseconds = watch.ElapsedMilliseconds;
                if (elapsedMilliseconds > expectedInMs)
                {
                    Log.Warn($"Performance Issue on '{name}, Expected:{ expectedInMs }ms, Actual: { elapsedMilliseconds }ms.");
                }

                return result;
            }
            catch (Exception)
            {
                Log.Error($"Performace Check '{name}' failed");
                throw;
            }
        }

        public static void Check(string name, Action action, long expectedInMs = 500)
        {
            try
            {
                // Run the benchmark.
                Stopwatch watch = Stopwatch.StartNew();
                action.Invoke();
                watch.Stop();

                // Output results.
                var elapsedMilliseconds = watch.ElapsedMilliseconds;
                if (elapsedMilliseconds > expectedInMs)
                {
                    Log.Warn($"Performance Issue on '{name}, Expected:{ expectedInMs }ms, Actual:{ elapsedMilliseconds }ms.");
                }
            }
            catch (Exception)
            {
                Log.Error($"Performace Check '{name}' failed");
                throw;
            }
        }
    }
}