type level =
| App
| Error
| Warning
| Info
| Debug
type ('a, 'b) msgf =
(?domain:Stdlib.Domain.id ->
?header:string ->
('a, Stdlib.Format.formatter, unit, 'b) Stdlib.format4 ->
'a) ->
'b
val debug : ('a, unit) msgf -> unit
val err : ('a, unit) msgf -> unit
val warn : ('a, unit) msgf -> unit
module Make (_ : sig ... end) : sig ... end