Typed handler with eventcallback

[thestonehead]

You last review was fair, but let me propose this approach.
If this is also not to your satisfaction, I'll stop.

This way, the support for .netstandard2.0 is maintained, however there's the price of handling different targets.

[soxtoby]

Can't say I'm a fan of this approach either, unfortunately. IEventHandler<T> having two methods for handling the same event seems like a confusing API to me - it's not clear from the interface which method will be called, or how the Handle method should be implemented if the HandleWithContext method is also implemented.

The current way to implement an event handler that requires the EventCallback is:

class MessageEventHandler : IEventHandler {
    public Task Handle(EventCallback eventCallback) {
        if (eventCallback.Event is MessageEvent message) {
            // Handle message
        }
    }
}

and the "improved" version would be:

class MessageEventHandler : IEventHandler<MessageEvent> {
    public Task Handle(MessageEvent slackEvent) => Task.CompletedTask;

    public Task HandleWithContext(MessageEvent slackEvent, EventCallback callback) {
        // Handle message
    }
}

As much as I agree it would be nice to have access to the EventCallback in typed handlers (all else being equal), I don't think the benefit here outweighs the cost in complexity, sorry.