stream: Readable.from with null

[ronag]

Reading through the Readable.from code is seems to me that the semantics of using Readable.from on a generator which yields null is not entirely clear.

Should we add a check for value == null and throw?

 async function next() {
 try {
 const { value, done } = await iterator.next();
 if (done) {
 readable.push(null);
 } else if (readable.push(await value)) { // Hm, push(null) and then next()?
 next();
 } else {
 reading = false;
 }
 } catch (err) {
 readable.destroy(err);
 }
 }

Might also want to be a bit more explicit in the docs about this?

[rexagod]

This makes sense. @ronag can I work on this?

[ronag]

Go for it.