feat(io/streams): Propagate cancel in readableStreamFromIterable()

[nayeemrmn]

Passes readable stream cancellations to the underlying iterator when applicable.

const readable = readableStreamFromIterable(async function* () {
  try {
    yield "foo";
  } catch (error) {
    console.log(error); // Error: Cancelled by consumer.
  }
}());
const reader = readable.getReader();
console.log(await reader.read()); // { value: "foo", done: false }
await reader.cancel(new Error("Cancelled by consumer."));

[kt3k]

LGTM. Nice!

[kt3k]

👍