sudo ip link set eth0 mtu 9000

You need to send a special packet.

Sending it via sudo because of raw sockets:

sudo ./venv/bin/python ./replay.py

To send it you need the capability to open sockets in raw mode, but that does not work well with scripts (see [1]

[1] setcap for executables, not helpful for python scripts:

setcap cap_net_raw,cap_net_admin=eip ./replay.py

if you don't already have a virtualenv. Linux specific, adjust to your OS.

virtualenv venv
. venv/bin/activate
pip install -r requirements.txt
(cd thermaldecoder; maturin develop -r)
python test_rust.py