Metrics

Awesome code, thanks a lot.

May you please consider to expose some metrics?
Such as: uptime, number of active sessions, message received, sent, droped (charset or bad format).

The issue names no files, tests, or entry points. Start by surveying the Rust data collector's server and message-handling areas, then clarify how uptime, active sessions, received, sent, and dropped messages should be exposed and defined. Done should include an agreed metrics interface and coverage for the requested measurements.

Written by the indexing model from the issue text.