Export synchronous function with a deferred fetch

Hi I have put together [this repo](https://github.com/rhodey/componentizejs-debug) with steps to reproduce.

ComponentizeJS is failing when:

1. exports a synchronous function.
2. the synchronous function starts deferred work (fetch).

Two branches have been prepared:

1. [main](https://github.com/rhodey/componentizejs-debug/tree/main) await is used and tests pass.
2. [poll](https://github.com/rhodey/componentizejs-debug/tree/poll) a polling mechanism is used and tests hang.

Repo includes all dependencies at latest versions at time of writing:

+ componentize-js 0.19.3
+ rust 1.93.0
+ wit-bindgen 0.53.1
+ wit-bindgen-rt 0.44.0
+ wstd 0.6.5

Repo README is very detailed

I cannot use await because I have read it is implemented as blocking the caller and my caller is an http server

Please do ask any and all questions and thanks for ComponentizeJS

先查看詳細的 README 和 issue 中連結的重現儲存庫，然後比較 main 和 poll 分支。執行 poll 分支以確認掛起行為，並將其與 await 分支進行對比。當同步匯出可以啟動延遲的 fetch 工作，且輪詢重現不會掛起時，即表示完成。

由索引模型根據 Issue 內容生成。