<PackageReference Include="NUnit" Version="3.0.0-alpha" />

Stopwatch

public class Stopwatch
This class wraps a System.Diagnostics.Stopwatch on operating systems that support it. On those that don't, it replicates the functionality at the resolution supported.
using System.Diagnostics; namespace NUnit.Framework.Compatibility { public class Stopwatch { private System.Diagnostics.Stopwatch _stopwatch = new System.Diagnostics.Stopwatch(); public long ElapsedMilliseconds => _stopwatch.ElapsedMilliseconds; public bool IsRunning => _stopwatch.IsRunning; public static long Frequency => System.Diagnostics.Stopwatch.Frequency; public static bool IsHighResolution => System.Diagnostics.Stopwatch.IsHighResolution; public static long GetTimestamp() { return System.Diagnostics.Stopwatch.GetTimestamp(); } public void Reset() { _stopwatch.Reset(); } public void Restart() { Reset(); Start(); } public void Start() { _stopwatch.Start(); } public static Stopwatch StartNew() { Stopwatch stopwatch = new Stopwatch(); stopwatch.Start(); return stopwatch; } public void Stop() { _stopwatch.Stop(); } public override string ToString() { return _stopwatch.ToString(); } } }