Improve juliacall startup time? #762

Currently, it takes more than 2 seconds to load the package juliacall in Python, before importing any Julia package or running Julia code:

$ time python -c "from juliacall import Main as jl"

real	0m2.355s
user	0m3.104s
sys	0m0.156s

This can be a disadvantage compared with calling C++ instead of Julia to offload heavy computations outside Python, depending on the workflow. Is there a way to compile a Julia system image to make the startup much faster?