AccountEventQueue

Buffers account/diagnostic events and flushes them to the backend in batches.

Telemetry must never affect a payment flow: every method here is fire-and-forget and every failure — a full queue, a transport error, a per-event rejection — is swallowed. Nothing this type does can throw to, or block, a caller.

In-memory only, by design: there is no disk persistence, so events still queued when the process dies are lost. A flush started from handleAppBackgrounded is best-effort — a POST begun at that point races process death and may never complete.

flushHandler is the seam for testing against a non-prod backend: the queue itself never reads networking constants, so a test supplies its own handler instead of the production AccountEventsAPI.record default.