The number of threads that have messages the current user hasn't seen yet and is subscribed to.
A user is automatically subscribed to threads relevant to them, for example because they have sent a message or have been @-mentioned in them. unreadSubscribed is always less than or equal to unread.
The hook will initially return undefined while the data loads from our API. Once it has loaded, your component will re-render and the hook will return an object containing the fields described under "Available Data" above. The component will automatically re-render if any of the data changes, i.e., this data is always "live".