Map: realtime vocabulary and the suspended connection

Destination

The realtime layer's names match what the code does, and a suspended connection cannot pass as a healthy one.

Notes

Domain: the DDP realtime layer (lib/drivers/) and the vocabulary in CONTEXT.md. Consumed by Rocket.Chat.ReactNative; the SDK ships TypeScript source with no build step, so every exported name is public API to that app.

Standing constraints for this effort:

• Mobile backgrounding is the driving case. iOS freezes the TCP socket silently — no close, no error — so connected keeps returning true and send() hangs awaiting 'open'. Android keeps listeners alive and delivers a burst on foreground. Same staleness number, opposite meanings.
• VoIP has a hard 10s deadline to reconnect and get a DDP event to the server. Every wait on the reconnect path spends from that one budget.
• Chat-history sync is out of scope — the consuming app already fetches messages since its last fetch over REST.
• lib/drivers/__tests__/ is a pinning suite: it locks current behaviour, quirks included. Identifier renames are mechanical there; behaviour changes are not.
• Skills: /domain-modeling for every glossary ticket, /grilling for the decisions.

Prior art consulted: the DDP spec, Meteor's client, @rocket.chat/ddp-client, and ten realtime chat SDKs (Matrix, Stream, Sendbird, Twilio, Slack, Pusher, Ably, Centrifugo, Phoenix, Strophe).

Decisions so far

• Connection states are named Open / Connected / Logged in.
• "Liveness chain" is dropped for Heartbeat, keeping upstream's three-way split: ping/pong are wire frames, heartbeat is the local timer, timeout is the dead-connection trigger. Probe stays — it has no upstream equivalent.
• Two kinds of message loss, and only one belongs here. Lost signal — an event sent between sub and the server's ready, gone permanently, no backfill possible, only avoidable by waiting for the ack — is this SDK's concern. Chat-history gaps are the consumer's and already handled.
• Suspended is adopted for a socket the OS froze that still reads as open. This unnamed state is the VoIP bug.
• Rocket.Chat's Impl suffix, no-I-prefix convention, uid, and its server-side "publication" term are not borrowed. Consistency with this repo wins, and "publication" has no referent here.
• Emitted event names are not renamed in this effort — they are wire-observable and pinned.

Not yet specified

• Whether the SDK should surface a "you were suspended" signal to the consuming app at all, or keep it internal to the reconnect path.
• Whether probe belongs on the public surface once Suspended is a named state.
• Whether the reconnect path needs a stated budget split per leg, which depends on what the measurements show.

Out of scope

• Chat-history gap recovery — the consuming app already syncs messages since its last fetch over REST. Building it here would duplicate it in the wrong layer.

Start with the realtime drivers in lib/drivers/, the vocabulary in CONTEXT.md, and the pinning tests under lib/drivers/tests/. Resolve the unspecified public-surface and reconnect-budget decisions, then document and test the agreed Open, Connected, Logged in, Suspended, Heartbeat, timeout, Probe, and Lost signal behavior without renaming emitted events.