Transform measurement: 50kbps, etc.

```
Should add an option to automatically transform the measurement? The best
practices doc's example kind of needs it. I'm thinking something like this:

@Override double transform(double originalNanos) {
return originalNanos / 100.0;
}

It would also be potentially useful to transform and supply a different unit:
@Units("kB/s") @Override double transform(double originalNanos) {
return (buffer.length / 1024.0) / (originalNanos * 1000000000);
}
```

Original issue reported on code.google.com by `limpbizkit` on 14 Aug 2010 at 6:28