timeout does not call return on source iterator

[backbone87]

https://github.com/ReactiveX/IxJS/blob/master/src/asynciterable/timeout.ts#L31

IxJS version: 2.5.3

Code to reproduce:

const ee = new EventEmitter();
try {
  const bar = await fromEvent(ee, 'foo').finally(() => void console.log('finally')).timeout(1000).take(1).toArray();
} catch (e) {
  console.log(e instanceof TimeoutError);
}

Expected behavior:
timeout returns the source iterator and therefore finally getting logged

Actual behavior:
timeout does not return the source iterator and therefore finally never gets logged

Additional information:
wrapping the whole while loop into a try ... finally works:

const it = this._source[Symbol.asyncIterator]();
try {
  while (1) {
    // ...
  }
} finally {
  await returnAsyncIterator(it);
}

also the timeout function is missing from AsyncIterableX.prototype

[backbone87]

seems finally itself has the same problem. do i get something wrong about the concept or are the intermediate iterables responsible for returning the source iterables?

[trxcllnt]

Got this implemented in the regular builds, but there seems to be a bug in closure-compiler: google/closure-compiler#3971