@SuppressWarnings({"rawtypes", "unchecked"})
      Entry<Object, V>[] entries = new Entry[size];
      for (int i = 0; i < size; i++) {
        // requireNonNull is safe because the first `2*size` elements have been filled in.
        Object key = requireNonNull(alternatingKeysAndValues[2 * i]);
        @SuppressWarnings("unchecked")
        V value = (V) requireNonNull(alternatingKeysAndValues[2 * i + 1]);

       */
      switch (size) {
        case 0:
          return of();
        case 1:
          // requireNonNull is safe because the first `size` elements have been filled in.
          Entry<K, V> onlyEntry = requireNonNull(entries[0]);
          return of(onlyEntry.getKey(), onlyEntry.getValue());
        default:
          break;
      }