code: public <K2 extends K, E2 extends E> BlockingList<K2, E2> make() {
          @SuppressWarnings("unchecked")
          BlockingListMaker<K2, E2> stricterThis = (BlockingListMaker<K2, E2>) this;
          return stricterThis.internalCreateBlockingList();
      }
docs: Construct a list