https://github.com/moby/buildkit

https://docs.docker.com/develop/develop-images/build_enhancements/

$ DOCKER_BUILDKIT=1 docker build .

2022
https://support.atlassian.com/bitbucket-cloud/docs/run-docker-commands-in-bitbucket-pipelines/#Enable-Docker-BuildKit
2021
Shulyak - Cook Dockerfiles Right of 59:02
    https://www.youtube.com/watch?v=Dx8WOurCCaM
    /etc/docker/daemon.json
    {"features":{"buildkit":true}}
    docker build --target ...
    RUN --mount=target=. ...
    docker run --rm -it --net container:nginx alpine
        to run container in the same network namespace as nginx