- Use the right number of printf() arguments. Use %q where it makes sense.
- Use "DRBD" instead of "Drbd", per Go's style guide.
- Add _total suffixes to counter metrics.
- Mention the unit (bytes) in documentation strings once more.
This collector exposes most of the useful information that can be found
in /proc/drbd. Sizes are normalised to be in bytes, as /proc/drbd uses
kibibytes.