- Wrap each prober function into a probe class that allows associating
metric labels and custom metrics with a given probe;
- Make sure all existing probe classes set a `class` metric label;
- Move bandwidth probe size from being a metric label to a separate
gauge metric; this will make it possible to use it to calculate
average used bandwidth using a PromQL query;
- Also export transfer time for the bandwidth prober (more accurate than
the total probe time, since it excludes connection establishment
time).
Updates tailscale/corp#17912
Signed-off-by: Anton Tolchanov <anton@tailscale.com>
5336362e64