Pi (eio.Eio.Process.Pi)

module type PROCESS = sig ... end

type Resource.pi +=

| Process : ('t, (module PROCESS with type t = 't and type tag = 'tag), [> 'tag ty ]) Resource.pi

val process : 
  (module PROCESS with type t = 't and type tag = 'tag) ->
  ('t, 'tag ty) Resource.handler

module type MGR = sig ... end

type Resource.pi +=

| Mgr : ('t, (module MGR with type t = 't and type tag = 'tag), [> 'tag mgr_ty ]) Resource.pi

val mgr : 
  (module MGR with type t = 't and type tag = 'tag) ->
  ('t, 'tag mgr_ty) Resource.handler