Stretched download?

[pmeenan]

TCP_NODELAY delays a partial-buffer write as long as there is pending un-ack'd data on the wire. As soon as the ack arrives it will flush the buffer (or wait until the timeout) so it will vary by the RTT for a certain amount.

Dev Tools traffic shaping (and PSI and Lighthouse) all operate in the application layer, well above the packet flow and won't expose packet-level pacing issues. Uf you use Network Link Conditioner (or winshaper) locally then you should be able to reproduce it.