Using the New API for Async Generators and Map Event to State

On on event API just allows you to register an event handler and on accepts a generic type for the event that you want to react to. With this new API now you're just using this emit function in both places so if you're using qubit and then you move to block it should feel a lot more familiar and the migration should be a lot simpler. It addresses some predictability issues that we are running into when using nested async generators with map event to state everything usually wasync generators.