"Patience" is a hint towards "time".
One can observe that HTTP server takes different time to respond. Sometimes it's ~100 ms, sometimes ~600 ms, sometimes ~1100 ms. Thus, some information could be transmitted using this covert timing channel.
We can interpret server delays as a morse code string. Delay >1000 ms is a space, delay >500 ms is a dash -, delay ~100 ms is a dot ..
Full solution using pyshark library: solution.py