Interface DiagnosticsEvent

One execution observation.

sequence is a dense per-instance counter shared by every event. Timing is monotonic relative to runtime initialization: atMs is the inclusive start offset and durationMs the inclusive elapsed time INCLUDING downstream next() work — a consumer must not sum parent and child durations as exclusive CPU time. Both are null for events recorded before the runtime (and therefore the monotonic origin) existed; fabricated timings are never emitted.

operationId links the event to its operation and is allocated at entry, so a child may reference a parent whose completion record appears later. parentOperationId is null for an operation root (a lifecycle boundary or the request operation itself).

statusCode, traceId, and spanId are optional: a status is present only on request/handler records that produced one, and trace identifiers are read only from an already-resolved telemetry service and validated before being carried — an absent, invalid, or throwing read is reported as absence.