Summary

A client side, per channel unread count for channels where serverside read events are disabled (typically livestream channels). When enabled, a user who scrolls away or reopens the app sees how many messages they've missed, even though the backend tracks no read state for that channel. Entirely client local, meaning no backend round trips for read state.

Motivation

Some channel types (e.g. livestreams) disable read events due to performance reasons (to reduce backend load), so the read-events own capability is off. As a result the server never reports per user read state or unread counts for those channels and the SDK's normal unread machinery short circuits. However, some integrations might still want a "you missed N messages" affordance. This feature reconstructs that count on the device as best it can.

Goals

• Optin, per channel unread count maintained on device for channels with disabled read-events
• Reuse the SDK's existing unread/read state machinery instead of forking it
• When resetting the count, the existing "mark channel read" flow clears the local count with no network call
• Safe no op for channels where read events are enabled and whenever the feature flag is off
• Updating the local DB with the local unread counts
• Local unread count should only work for the our own user, not for all channel members (as it clearly cannot)

Out of scope

• Total/aggregate unread (the user level unread count across all channels) remains unaffected
• Thread level unread (the per thread reply badge in ThreadList for example) remains a separate subsystem, not is not covered
• Mark unread (manually marking a channel unread locally) also not in scope
• Cross device consistency (using the SDK on 2 devices) also not covered, explicitly per device

The general idea is that we keep a session, local only count and accept the fact that it cannot be perfectly synced with the (non-existing) backend read objects.

Configuration contract

A single client level boolean flag, defaulting to false.

• isLocalUnreadCountEnabled - a new variable applied to client config in the low level client