handle merging additional Request / Response instance properties

[thescientist13]

Summary

As part of #948, we created a utility in resource-utils.js to merge Response objects when needed, but it doesn't currently support anything other body and headers.

return new Response(source.body, {
  headers
});

In addition, instances of Request are missing critical properties like body, which means Greenwood is totally unusable for handling POST requests
https://github.com/ProjectEvergreen/greenwood/blob/v0.28.5/packages/cli/src/lifecycles/serve.js#L37

  const initRequest = new Request(url, {
    method: ctx.request.method,
    headers: new Headers(ctx.request.header)
  });

Details

I would like to make sure that we can merge all relevant Response instance properties like

• status
• statusText
• Custom headers like Content-Length

And Request instance properties

• method
• body (make sure it supports json, formData, etc)
• integrity
• referrer
• referrerPolicy
• all of them?

Needs to be done in

• the serve.js lifecycle as needed.
• API routes for local dev - bug/use Worker threads for full API routes cache busting in development mode #1105
• Adapter Plugins

---

Bonus points for handling the Range header (good link here on implementation) which I think will fix this issue with serving media on Safari

Error: read ECONNRESET
at TCP.onStreamRead (node:internal/stream_base_commons:217:20)

[thescientist13]

See #1146 and #1147 for follows up on this work