[kg]

It's a real shame that BYOB (bring your own buffer) reads are so complex and such a pain in the neck because for large reads they make a huge difference in terms of GC traffic (for allocating temporary buffers) and CPU time (for the copies).

In an ideal world you could just ask the host to stream 100MB of stuff into a byte array or slice of the wasm heap. Alas.

[amluto]

I wonder if you can get most of the benefit BYOB with a much simpler API:

    for await (const chunk of stream) {
        // process the chunk
        stream.returnChunk(chunk);
    }

This would be entirely optional. If you don’t return the chunk and instead let GC free it, you get the normal behavior. If you do return it, then the stream is permitted to return it again later.

(Lately I’ve been thinking that a really nice stream or receive API would return an object with a linear type so that you must consume it and possibly even return it. This would make it impossible to write code where task cancellation causes you to lose received data. Sadly, mainstream languages can’t do this directly.)