private ConcurrentLinkedDictionary <K, IEnumerable <V> > newEmptyWeightedMap <K, V>()
 {
     return(new Builder <K, IEnumerable <V> >()
            .MaximumWeightedCapacity(Capacity())
            .Weigher(Weighers.Enumerable <V>())
            .Build());
 }
        private ConcurrentLinkedDictionary <K, IEnumerable <V> > newGuardedWeightedMap <K, V>()
        {
            var listener = guardingListener <K, IEnumerable <V> >();

            return(new Builder <K, IEnumerable <V> >()
                   .MaximumWeightedCapacity(Capacity())
                   .Weigher(Weighers.Enumerable <V>())
                   .Listener(listener)
                   .Build());
        }