stream polyfill about node_deno_shims

[MKRhere]

Awesome, @jimmywarting!

We'd considered vendoring fetch-blob to add WHATWG streams, good to know it's upstream now.

Thanks for letting us know. This solves many problems.

[trgwii]

Unfortunately we can't use fetch-blob since it only has ESM, so currently we are exporting nodejs's require('buffer').Blob and importing fetch-blob/streams.cjs only in deno.ns/global, to polyfill the global.

This project will probably convert to ESM eventually, but not right now.

It would have been useful if we could also import ReadableStream / WritableStream / other WhatWG Stream utils directly from fetch-blob somehow, and not have it automatically add them to globalThis, as we want to manage global polyfills ourselves (not polyfill anything by default, but let the user opt-in by importing deno.ns/global)