module Postmark : sig ... end
module Message : sig ... end
module type With_container : sig ... end
module With_lazy_list : With_container with type t = Message.t Core_extended.Std.Lazy_list.t
module With_seq : With_container with type t = Message.t Core_extended.Std.Lazy_sequence.t
Warning: When created from a file descriptor, the resulting mailbox can only be traversed once.
module With_pipe : sig ... end