Probably missing ability to dispatch non-typed messages

[razenpok]

Hi again,

I have a use-case of message forwarding from a different event bus. This event bus can dispatch generic-typed events as well as an ability to handle all the events in a single general handler, in which case the dispatched event will be passed as an object.

// e here is an `object` which cannot be dispatched to a generic AsyncMessageBus handler
DomainEvents.RegisterGeneralHandler(e => AsyncMessageBus.Default.PublishAsync(e));

An easy fix here would be to add an overload that accepts object as a msg argument and just msg.GetType(). Probably it is not needed in UniTaskPubSub or maybe there's a better way to do this, but right now I'm not sure how to deal with this issue without Reflection.

[hadashiA]

Hi :)

Ok, I'm going to consider adding a Non-Generic version of Publish.

However, the current Generic version of Publish does not have boxing allocation, while the Non-Generic version definitely has boxing and will degrade performance compared to the Generic version.

--

Another way to do msg.GetType() might be to cast the object.

switch (msg)
{
    case msg is MessageA x:
        PublishAsync(x);
        break;
    case msg is MessageB x:
        PublishAsync(x);
        break;
    default:
        throw new NotImplementationException();
}

Yes, we can use the This is a pain.
But maybe we can do automatic code generation.

[razenpok]

Oof

Again, most likely it's not worth it. As you said, it will have performance implications, but more than that it adds some sematics which might be not clear:

AsyncMessageBus.Default.Subscribe(Handler)

UniTask Handler(object message)

Does this code mean that Handler will handle any possible message? Looks like it should if Non-Generic publish is introduced. And after that the question of polymorphic dispatch can arise. Similar thing is done in MediatR

https://github.com/jbogard/MediatR/wiki#polymorphic-dispatch

But this feature might be an overkill for a Unity message bus, since performance is paramount in gamedev.