K2.Bucketval make : unit -> ('k1, 'k2, 'd) tCreate a new bucket.
val add : ('k1, 'k2, 'd) t -> 'k1 -> 'k2 -> 'd -> unitAdd an ephemeron to the bucket.
val remove : ('k1, 'k2, 'd) t -> 'k1 -> 'k2 -> unitremove b k1 k2 removes from b the most-recently added ephemeron with keys k1 and k2, or does nothing if there is no such ephemeron.
val find : ('k1, 'k2, 'd) t -> 'k1 -> 'k2 -> 'd optionReturns the data of the most-recently added ephemeron with the given keys, or None if there is no such ephemeron.
val length : ('k1, 'k2, 'd) t -> intReturns an upper bound on the length of the bucket.
val clear : ('k1, 'k2, 'd) t -> unitRemove all ephemerons from the bucket.