`vouch_ready` is a prometheus metric that is `0` if Vouch is not yet
ready to validate, and `1` if it is.
`vouch_release` has a labeled value `version` that contains the release
version of Vouch.
This adds a label `epoch_slot` to the prometheus metric
`vouch_block_receipt_delay_seconds`. It has been noted that the receipt
delay is often significantly higher for the first (and, to a lesser
extent, second) slot in a given epoch. This allows the receipt delay to
be examined for specific slots in a given epoch.
This metric used to count the number of internal attestation processes
carried out, however a single attestation process can involve multiple
validators if they are attesting in the same slot and committee. This
fix ensures that the metrics reflect the number of attestations, not the
number of processes.
Jim McDonald