bug#22745: guix http downloads don't resume

[Danny Milosavljevic]

Package: guix

By now, guix reconfigure has tried to download the same texlive binary from 
hydra at least 5 times to the same machine, unsuccessfully breaking after about 
1 GB each, for a total of 5 GB, always starting from the beginning.

Would it be possible to just resume?

Additionally, it doesn't seem like it checks the Content-Length in order to 
find out whether the connection broke before the file was done. Why doesn't it?

The http-client seems to handle chunked encoding - so not sure whether it's a 
problem with hydra or with guix.