Batteries.Mutex

`sig
module Mutex :
sig
type t = Mutex.t
val create : unit -> t
val lock : t -> unit
val try_lock : t -> bool
val unlock : t -> unit
val synchronize : ?lock:t -> ('a -> 'b) -> 'a -> 'b
val make : unit -> BatConcurrent.lock
end
module DebugMutex :
sig
type t = BatMutex.DebugMutex.t
val create : unit -> t
val lock : t -> unit
val try_lock : t -> bool
val unlock : t -> unit
val synchronize : ?lock:t -> ('a -> 'b) -> 'a -> 'b
val make : unit -> BatConcurrent.lock
end
end`