`sig
type t
val create : ('a -> 'b) -> 'a -> Cothread.t
val self : unit -> Cothread.t
val id : Cothread.t -> int
val exit : unit -> unit
val delay : float -> unit
val join : Cothread.t -> unit
val wait_timed_read : Unix.file_descr -> float -> bool
val wait_timed_write : Unix.file_descr -> float -> bool
val select :
Unix.file_descr list ->
Unix.file_descr list ->
Unix.file_descr list ->
float ->
Unix.file_descr list * Unix.file_descr list * Unix.file_descr list
val wait_pid : int -> int * Unix.process_status
val yield : unit -> unit
val wait_signal : int list -> int
val spawn : ('a -> 'b) -> 'a -> 'b Event.event
val spawnl : ('a -> 'b) -> 'a -> 'b Event.event
end`