goodbye, world!

Code flow:

    1: main::one
    2: main::two
    3: main::three

Stack trace:

    in:      main::one
    sub:     -
    file:    ./trace.pl
    line:    8
    package: main

    in:      main::two
    sub:     main::one
    file:    ./trace.pl
    line:    19
    package: main

    in:      main::three
    sub:     main::two
    file:    ./trace.pl
    line:    27
    package: main