The same typeahead session with a fresh client_uuid_rank_token: each query
carries its own rank token while typeahead_session_id stays for the whole
typing session. The search field's change action is its only caller; it is
not part of the public surface.
The same typeahead session with a fresh
client_uuid_rank_token: each query carries its own rank token whiletypeahead_session_idstays for the whole typing session. The search field'schangeaction is its only caller; it is not part of the public surface.