Interface RealtimeDiagnosticsRecord

Cumulative counters for one realtime operation of one source (M98l).

Every settled observation increments count and exactly one of succeeded or failed; every counter saturates at Number.MAX_SAFE_INTEGER. backpressureCloses is a number only for an sse source's close record — the closes its backlog guard caused, a subset of failed — and null everywhere else, so a measured zero is distinguishable from "not supported". lastDurationMs is a number only for backplane-publish, the one operation that settles asynchronously; every other operation is instantaneous and carries null. ageMs is monotonic time since the most recent observation. A record expires 60 seconds after its last observation. No frame, message, name, identifier, close reason or error is ever carried.