What problem does this feature solve?

Currently, when referencing @rsbuild/core/types, ImportMeta type is

interface ImportMeta {
    url: string;
    // TODO: unsupported
    // webpack: number;
    webpackHot: Rspack.Hot;
   // ...
}

Cann we make webpackHot be optional, so that it matches the documentation that it may not necessarily exist? (If I got it right, during SSR it does not exist, if this is not expected I'll fire a bug report)
https://rspack.rs/api/runtime-api/hmr#example

What does the proposed API look like?