<Query Kind="Program">
  <Namespace>System.Threading.Tasks</Namespace>
</Query>

async Task Main()
{
	_lastLog = DateTime.Now;
	using (var defaultWatcher = new FileSystemWatcher())
	{
		defaultWatcher.Dump("default FileSystemWatcher");
	}

	var workingDir = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName());
	Directory.CreateDirectory(workingDir);

	using (var watcher = new FileSystemWatcher
	{
		EnableRaisingEvents = false,
		Filter = "*.*",
		IncludeSubdirectories = false,
		InternalBufferSize = 8192,
		NotifyFilter = NotifyFilters.FileName | NotifyFilters.DirectoryName | NotifyFilters.LastWrite,
		Path = workingDir, // default: "",
		Site = null,
		SynchronizingObject = null,
	})
	{
		watcher.Changed += (obj, evt) => Log(evt, "Changed");
		watcher.Created += (obj, evt) => Log(evt, "Created");
		watcher.Deleted += (obj, evt) => Log(evt, "Deleted");
		watcher.Error += (obj, evt) => Log(evt, "Error");
		watcher.Renamed += (obj, evt) => Log(evt, "Renamed");

		watcher.EnableRaisingEvents = true;

		Log(@"File.WriteAllText(""derp.txt"", ""derp"")");
		File.WriteAllText(Path.Combine(workingDir, "derp.txt"), "derp");
		await Task.Delay(TimeSpan.FromMilliseconds(10));

		Log(@"File.WriteAllText(""derp.txt"", ""derp"") // again");
		File.WriteAllText(Path.Combine(workingDir, "derp.txt"), "derp");
		await Task.Delay(TimeSpan.FromMilliseconds(10));

		Log(@"File.Open(""derp.txt"", FileMode.Open)");
		using (var f = File.Open(Path.Combine(workingDir, "derp.txt"), FileMode.Open, FileAccess.ReadWrite, FileShare.ReadWrite))
		using (var stream = new StreamWriter(f))
		{
			await Task.Delay(TimeSpan.FromMilliseconds(10));


			Log(@"stream.WriteLine(""some text"")");
			await stream.WriteLineAsync("some text");
			await Task.Delay(TimeSpan.FromMilliseconds(10));

			Log(@"stream.Dispose()");
		}
		await Task.Delay(TimeSpan.FromMilliseconds(10));

		Log(@"File.Move(""derp.txt"", ""herp.txt"")");
		File.Move(Path.Combine(workingDir, "derp.txt"), Path.Combine(workingDir, "herp.txt"));
		await Task.Delay(TimeSpan.FromMilliseconds(10));

		Log(@"File.Delete(""herp.txt"")");
		File.Delete(Path.Combine(workingDir, "herp.txt"));
		await Task.Delay(TimeSpan.FromMilliseconds(10));
	}

	Directory.Delete(workingDir);
}

static DateTime _lastLog;
static object _lock = new object();

static void Log(object message, string description=null)
{
	lock (_lock)
	{
		var now = DateTime.Now;

		var timestamp = $"{now.ToString("HH:mm:ss.fff")} (+{Math.Round((now - _lastLog).TotalMilliseconds)}ms)";
		if (message is string)
			Console.WriteLine($"{timestamp}: {message}");
		else
		{
			Console.WriteLine(timestamp + (string.IsNullOrEmpty(description) ? string.Empty : ": " + description));
			LINQPad.Extensions.Dump(Util.ToExpando(message));
		}
		_lastLog = now;
	}
}