Module Make.Transform

type t
val append' : (Message_event.t -> Message_event.t option) -> t
val prepend' : (Message_event.t -> Message_event.t option) -> t
val append : (Message_event.t -> Message_event.t) -> unit
val prepend : (Message_event.t -> Message_event.t) -> unit
val remove_exn : t -> unit