Function eligibility 

fn eligibility(
    update_token: u64,
    globalsince: u64,
    next_batch: u64,
    roomsince: u64,
    has_users: bool,
) -> Option<bool>

Whether a typing update publishes, and if so whether only alongside an initial room payload.

None skips the room; Some(false) is a live update, empty clears included; Some(true) is an initial candidate gated later on an actual initial payload.