- metrics package with collectors for metrics, and a context based API for instrumenting code with minimal intrusion from the metrics library.
- TTYRenderer for live view of metrics as they update.
- Calls to metrics have replaced logging as the primary mechanism for communicating progress to an interactive user.  Logging will still have a place in the server processes (e.g. serve, serve-quic).
- package `units` provides unit and SI Prefix constants and utilities.