Firefox 134.0.1: Download stops when throughput exceeds a threshold (around 1-10 MiB/s)

[llaurenss]

In Firefox 134.0.1, downloads are incorrectly marked as finished after only a few seconds if the download throughput exceeds a certain threshold. This threshold appears to vary between 1 MiB/s and 10 MiB/s depending on chunk size and write interval.

Can very easily be reproduced here: https://llaurenss.github.io/streamsaver-throughput-demo/

Firefox version 134.0 works fine, its the 134.0.1 update that introduced this problem https://www.mozilla.org/en-US/firefox/134.0.1/releasenotes/

[llaurenss]

Fixed in 134.0.2 https://www.mozilla.org/en-US/firefox/134.0.2/releasenotes/