Entry<K, V> onlyEntry = requireNonNull(entries[0]);
          return of(onlyEntry.getKey(), onlyEntry.getValue());
        default:
          break;
      }
      // localEntries is an alias for the entries field, except if we end up removing duplicates in
      // a copy of the entries array. Likewise, localSize is the same as size except in that case.

       * affect the original array), and future build() calls will always copy any entry
       * objects that cannot be safely reused.
       */
      // localAlternatingKeysAndValues is an alias for the alternatingKeysAndValues field, except if
      // we end up removing duplicates in a copy of the array.
      @Nullable Object[] localAlternatingKeysAndValues;
      int localSize = size;