AuthError means that an authentication error has occurred.
Broadcast means that a broadcast message has been received.
Initialized means that the presence watch has been initialized.
LocalBroadcast means that a broadcast message has been sent by the local client.
Changed means that the presence has changed.
SyncError means that a non-recoverable sync (RefreshChannel) error
occurred. Subscribers can use this to render an error state in the UI
without polling internal SDK state. The SDK still retries via its sync
loop, so subsequent successful events (PresenceChanged/Initialized) can
be treated as recovery.
ChannelEventTyperepresents the type of channel event.