Add "logging" alias to the example, to make it work.

Without it, i am getting :
    ./example.go:5: undefined: logging
    ./example.go:10: undefined: logging
    ./example.go:19: undefined: logging
    ./example.go:24: undefined: logging
    ./example.go:25: undefined: logging
    ./example.go:30: undefined: logging
    ./example.go:33: undefined: logging
    ./example.go:34: undefined: logging
    ./example.go:37: undefined: logging