fix(worker-build): prevent script will never generate a response

[samdenty]

This fixes https://github.com/cloudflare/workers-rs/issues/255

There's no clean way to convert the index_bg.js which contains ESM exports, into a function which is called on each fetch().

So in this PR, I basically split the two parts of the bundle up and move the initialization inside the fetch function, by replacing the INSERT_INIT() token

This is kinda hacky, but it works. It fixes the script will never generate a response errors that can occur when sharing the wasm state across requests.

[samdenty]

ping @zebp i wonder if you know who to hit up to get this in, this is blocking me from using worker-rs

[zebp]

ping @zebp i wonder if you know who to hit up to get this in, this is blocking me from using worker-rs

left a reply in the issue

[Smephite]

Is there any update on this?