NServiceBus - Touch a heartbeat file for external watchdog like monitoring

HeartbeatTouchBehavior.cs

using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using NServiceBus.Pipeline;

sealed class HeartbeatTouchBehavior : Behavior<IIncomingLogicalMessageContext>
{
    static readonly string filePath = "C:/watchdog/heartbeat.txt";
    static readonly TimeSpan interval = TimeSpan.FromMinutes(1);
    static DateTime lastTouched = DateTime.MinValue;
    static readonly object sync = new();

    public override Task Invoke(IIncomingLogicalMessageContext context, Func<Task> next)
    {
        var now = DateTime.UtcNow;

        if ((now - lastTouched) >= interval)
        {
            lock (sync)
            {
                if ((now - lastTouched) >= interval)
                {
                    TouchFile(filePath);
                    lastTouched = now;
                }
            }
        }

        return next();
    }

    static void TouchFile(string path)
    {
        Directory.CreateDirectory(Path.GetDirectoryName(path)!);

        if (File.Exists(path))
            File.SetLastWriteTimeUtc(path, DateTime.UtcNow);
        else
            using var _ = File.Create(path); // create empty file
    }
}