Local development notes:

Server:  (TLS stuff is optional)
$ go run $GOROOT/src/crypto/tls/generate_cert.go --host=example.com
$ GCEMETA_password=foo GCEMETA_tls_cert=@cert.pem GCEMETA_tls_key='@key.pem' ./buildlet

Client:
$ curl -O https://go.googlesource.com/go/+archive/3b76b017cabb.tar.gz
$ curl -k --user :foo -X PUT --data-binary "@go-3b76b017cabb.tar.gz" https://localhost:5936/writetgz
$ curl -k --user :foo -d "cmd=src/make.bash" http://127.0.0.1:5937/exec
etc