Thread replies do not local echo as expected

[davidisaaclee]

When sending an event as a reply to a thread using the default "chronological" pendingEventOrdering, I'd expect the reply to appear in the thread's timeline as soon as sendMessage is called. In actuality, with [email protected], the event only shows up in the thread's timeline about half a second after the sendMessage promise resolves.

(I'd also be fine with the local echo appearing in the thread's containing Room, but no dice there either.)

Here is a branch of a repo that I think has a minimal reproducing example, although it's a little noisy due to many Thread.updates called – I believe related to #3463. (I don't think this is caused by the same bug as #3463 though, as this happens for me in threads with fewer than 11 events.)

Here are logs of me running this code: