Significant performance optimizations possible in `requestResponseMessage`

I'm using Comlink on a Deno server that is handling a lot of traffic - I'm just passing a string to the worker, and then the worker is sending back ArrayBuffers (I'm using `Comlink.transfer` for sending those, of course), and it turns out that Comlink has become a bottleneck on the main thread - specifically this code:


I'd have thought that V8 would have some magic optimizations to make the function creation here not as expensive as it seems to be. It looks like it's creating a "fresh" function each time, and then isn't able to optimize it since it only gets called once, and so simple stuff like `!ev.data || !ev.data.id` runs slow because it's basically running in "interpreted" mode. That's my guess here, anyway.

I'm wondering if you'd welcome a pull request which optimizes this, and if so, do you have any preferred approach? My thinking here is that you'd just have a single function (rather than creating a new one for every request), and it uses a `Map` which maps an `id` to its `resolver`.