Client now has three send channels:
- sendHigh (64 slots): DMs, mentions — drained first by writePump
- send (256 slots): chat messages, reactions — drained second
- sendLow (64 slots): typing, presence — drained last, dropped on overflow
writePump drains high-priority messages before checking normal/low.
PubSub gains PublishHigh/PublishLow alongside existing Publish.
EmitEvents routes events by priority:
- High: SequencedDMEvent, UserTargetedEvent
- Normal: ChannelEvent, VoiceChannelEvent
- Low: ExcludeSenderEvent (typing), PresenceEvent
Slow clients get typing/presence dropped first (sendLowMsg silently
drops), then disconnect on normal buffer overflow, ensuring DMs are
never lost to typing indicator backpressure.
https://claude.ai/code/session_01CBFF3r84ywkJRWwuqw8zD8
PublishLowPriority uses trySendMsg to silently drop messages when a
client's buffer is full, instead of disconnecting them. This provides
priority-based backpressure: chat messages use normal Publish (disconnect
on overflow), while ephemeral events like typing indicators and presence
updates use PublishLowPriority (drop on overflow).
https://claude.ai/code/session_01CBFF3r84ywkJRWwuqw8zD8
Introduce topic-based PubSub for O(subscribers) message routing:
- Clients subscribe to "global" and "user:{id}" on connect
- Channel broadcasts route through "channel:{id}" topics
- deliverBroadcast() uses PubSub instead of iterating all clients
- UnsubscribeAll on disconnect/kick cleans up subscriptions
- Sequence numbering and replay buffer preserved unchanged
https://claude.ai/code/session_01CBFF3r84ywkJRWwuqw8zD8
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