This driver allows creating a buildx instance directly pointing to the existing buildkit endpoint.

docker buildx create --driver=env unix:///var/lib/buildkitd.sock
docker buildx create --driver=env uses BUILDKIT_HOST env value with UNIX sock default.

I guess TLS info is just passed with a custom driver-opt:

docker buildx create --driver=env --driver-opt ca=mycafile.pem https://foobar

rm/stop commands are no-op in this driver.

A better name could be "remote".