Development: Loading main.chunk.js is unbearably slow (using qa-tunnel.gitlab.info)

Serving the same Javascript file takes a long time if we proxy it over qa-tunnel.gitlab.info, averaging around 1 minute.

time wget http://localhost:8081/assets/webpack/main.chunk.js
real	0m0.096s

time wget https://24046.qa-tunnel.gitlab.info/assets/webpack/main.chunk.js
real	1m8.306s

Workaround

Start GDK with NO_SOURCEMAPS=true - this reduces the size of main.chunk.js to upload