I have a process that needs to intermittently move some files from one directory to another. Before I move the files, I need to ensure that a user isn't currently adding files to the directory - if they are, I want to wait until no new files have been added to the directory for N seconds before continuing the process (the value of N doesn't really matter here).

My original idea was to use a FileSystemWatcher to capture file creation events, use the .Throttle() method from Rx to get the last event generated within the specified period of time, and use result of that to disable an infinite delay loop. The problem is, this method will just wait forever if a user never makes any changes to the directory. Somehow, I need this to wait at least N seconds, and if there is no change within that period of time, continue. If there is a change within that period of time, then wait until N seconds have passed since the last change.

Here's what I have so far:

Console.WriteLine("start");

// wait to ensure no changes are being made to the directory
await Task.Run(async () =>
{
    var watcher = new FileSystemWatcher("D:\\Users\\mwcjk1\\source\\repos\\RandomTestAppNet8\\RandomTestAppNet8\\");
    watcher.EnableRaisingEvents = true;

    watcher.Created += (o, a) => { Console.WriteLine("file changed!"); };

    var subject = Observable.FromEventPattern<FileSystemEventHandler, FileSystemEventArgs>(
        ev => watcher.Created += ev,
        ev => watcher.Created -= ev
        );

    bool done = false;

    // wait for 7 seconds after the last file creation
    var disposable = subject.Throttle(TimeSpan.FromSeconds(7)).Subscribe(events => { done = true; });

    Console.WriteLine("Set up observer");

    while (!done)
    {
        await Task.Delay(1000);
        //Console.WriteLine("Waited 1 sec");
    }

    disposable.Dispose();
});

// Continue with the rest of the method execution
Console.WriteLine("done!");

I also don't like the Task.Delay() loop - it feels like there should be a much more elegant way of doing this (.Throttle() seems so close to working on its own!), but I haven't been able to figure it out.

Any advice is much appreciated, thanks!