Option to await until a `TrackHandle` is finished playing

[Sir-Photch]

I suggest adding some way for TrackHandle returned by Driver.play_source() to be awaited, for the future to be finished when the played input is finished.

I have this implemented the following way:

let (call, result) = manager.join( .... ).await;
let player = call.lock().await.play_source(....);
if let Some(duration) = player.metadata().duration {
    tokio::time::sleep(duration).await;
}

Maybe this is something that would be of use for the API?

[FelixMcFelix]

The correct way to do something like this is to use the existing event system: have a look at the queue implementation to get a feel for how tracks can handle an event on end.

I think a utility function that makes use of this might be useful though, if a little tough to get right ergonomically. I.e., you want to register events before you play a track to ensure no Ends can be missed (though this should only be possible on 0--20ms sources), but naturally you have to play it after registering the event!

[Sir-Photch]

I see. I am not sure though, if this applies to my usecase.

I think a utility function that makes use of this might be useful though, if a little tough to get right ergonomically.

Well, what if .play_source() returns a tuple consisting of the player as well as some handle that can be joined? Then, the events could be registered internally, before the actual process of playing the input starts.

[FelixMcFelix]

Well, what if .play_source() returns a tuple...

The problem with doing this is that every single user now pays for an extra event registration, channel allocation, etc. – it isn't zero-cost, regardless of whether they use the feature or not. So this is unlikely to happen.

You could also attach a global event handler to the End event, and simply store a one-shot channel for each needed UUID. All you need to do is await a response on the channel to get the same semantics.