module Make:
type 'a t
val create : unit -> 'a t
val enqueue : 'a t ->
key:Key.t -> ('a option -> 'b Import.Deferred.t) -> 'b Import.Deferred.t
enqueue t ~key f enqueues f for key. f will be called with the state of
key when invoked. If there is no pending job for key, f will be called
immediately. If f raises, then the exception will be raised to the monitor in
effect when enqueue was called. Subsequent jobs for key will proceed.
val set_state : 'a t -> key:Key.t -> 'a option -> unit
set_state t key state_opt sets the state for key immediately. The state will be
kept internally until set to None
val find_state : 'a t -> Key.t -> 'a option
val num_unfinished_jobs : 'a t -> Key.t -> int
num_unfinished_jobs t key returns the number of jobs for key including including
pending and running.
val mem : 'a t -> Key.t -> bool
mem t key returns true if there is state or an pending/running job
val fold : 'a t ->
init:'b -> f:('b -> key:Key.t -> 'a option -> 'b) -> 'b
Fold over keys with states or pending/running jobs. It's safe to mutate (enqueue
or set_state) when folding