`'t Uq_engines_compat.engine_state ->
Unixqueue.event_system ->
object
method event_system : Unixqueue.event_system
method private notify : unit -> unit
method request_notification : (unit -> bool) -> unit
method request_proxy_notification :
('t Uq_engines_compat.engine -> bool) -> unit
method private set_state : 't Uq_engines_compat.engine_state -> unit
method state : 't Uq_engines_compat.engine_state
end`