Runtime_events.Callbacksval create :
?runtime_begin:(int -> Timestamp.t -> runtime_phase -> unit) ->
?runtime_end:(int -> Timestamp.t -> runtime_phase -> unit) ->
?runtime_counter:(int -> Timestamp.t -> runtime_counter -> int -> unit) ->
?alloc:(int -> Timestamp.t -> int array -> unit) ->
?lifecycle:(int -> Timestamp.t -> lifecycle -> int option -> unit) ->
?lost_events:(int -> int -> unit) ->
unit ->
tval add_user_event :
'a Type.t ->
(int -> Timestamp.t -> 'a User.t -> 'a -> unit) ->
t ->
t