HashMap.StringSpecalized when key type is string, more efficient than the generic type
val make : hintSize:int -> 'b tval clear : 'b t -> unitval isEmpty : _ t -> boolsetDone tbl k v if k does not exist, add the binding k,v, otherwise, update the old value with the new v
val forEachU : 'b t -> (key -> 'b -> unit) Js.Fn.arity2 -> unitval reduceU : 'b t -> 'c -> ('c -> key -> 'b -> 'c) Js.Fn.arity3 -> 'cval keepMapInPlaceU : 'a t -> (key -> 'a -> 'a option) Js.Fn.arity2 -> unitval size : _ t -> intval valuesToArray : 'a t -> 'a arrayval getBucketHistogram : _ t -> int arrayval logStats : _ t -> unit