How to: What mirrors are appropriate to use to build Docker-OSX locally?
If you are building Docker-OSX locally, you'll probably want to use Arch Linux's mirrors.

Mirror locations can be found here (uses two-letter country codes): https://archlinux.org/mirrorlist/all/

```bash
docker build -t docker-osx:latest \
    --build-arg RANKMIRRORS=true \
    --build-arg MIRROR_COUNTRY=US \
    --build-arg MIRROR_COUNT=10 \
    --build-arg SHORTNAME=catalina \
    --build-arg SIZE=200G .
```