Benchmark.NET with Stopwatch

BenchmarkDotnet_Stopwatch.cs

async Task Main()
{
    var summary = BenchmarkRunner.Run<BenchmarkTarget>();
//    var sw = ValueStopwatch.StartNew();
//    await Task.Delay(1 * 1000);
//    sw.GetElapsedTime().Dump();
//    await Task.Delay(1 * 1000);
//    sw.GetElapsedTime().Dump();
//    await Task.Delay(1 * 1000);
//    sw.GetElapsedTime().Dump();
//
//    var sw2 = ValueStopwatch.StartNew();
//    await Task.Delay(1 * 1000);
//    sw.GetElapsedTime().Dump("sw");
//    sw2.GetElapsedTime().Dump("sw2");
//
//    var sw3 = ValueStopwatch.StartNew();
//    await Task.Delay(1 * 1000);
//    sw.GetElapsedTime().Dump("sw");
//    sw2.GetElapsedTime().Dump("sw2");
//    sw3.GetElapsedTime().Dump("sw3");
}

[ShortRunJob]
[MemoryDiagnoser]
public class BenchmarkTarget
{
    [Benchmark]
    public void Stopwatch()
    {
        for (var i = 0; i < 10000; i++)
        {
            var sw = System.Diagnostics.Stopwatch.StartNew();
            sw.Stop();
        }
    }

    [Benchmark]
    public void ValueStopwatch()
    {
        for (var i = 0; i < 10000; i++)
        {
            var sw = UserQuery.ValueStopwatch.StartNew();
            sw.GetElapsedTime();
        }
    }
}

public struct ValueStopwatch
{
    private static readonly double TimestampToTicks = TimeSpan.TicksPerSecond / (double)Stopwatch.Frequency;

    private long _startTimestamp;

    public bool IsActive => _startTimestamp != 0;

    private ValueStopwatch(long startTimestamp)
    {
        _startTimestamp = startTimestamp;
    }

    public static ValueStopwatch StartNew() => new ValueStopwatch(Stopwatch.GetTimestamp());

    public TimeSpan GetElapsedTime()
    {
        // Start timestamp can't be zero in an initialized ValueStopwatch. It would have to be literally the first thing executed when the machine boots to be 0.
        // So it being 0 is a clear indication of default(ValueStopwatch)
        if (!IsActive)
        {
            throw new InvalidOperationException("An uninitialized, or 'default', ValueStopwatch cannot be used to get elapsed time.");
        }

        var end = Stopwatch.GetTimestamp();
        var timestampDelta = end - _startTimestamp;
        var ticks = (long)(TimestampToTicks * timestampDelta);
        return new TimeSpan(ticks);
    }
}