You can search for identifiers within the package.
in-package search v0.2.0
type tx
type rx
type 'a req
type 'a res
type mgr
type src
type dst
val request : mgr -> ?src:src -> dst -> tx req -> rx res Lwt.t
val respond : mgr -> src -> (dst -> rx req -> tx res Lwt.t) -> unit Lwt.t