private static final int HASH_TABLE_BITS_MAX_BITS = 5;

  /** Use high bits of metadata for modification count. */
  static final int MODIFICATION_COUNT_INCREMENT = (1 << HASH_TABLE_BITS_MAX_BITS);

  /** Bitmask that selects the low bits of metadata to get hashTableBits. */
  static final int HASH_TABLE_BITS_MASK = (1 << HASH_TABLE_BITS_MAX_BITS) - 1;

  /** Maximum size of a compact hash-based collection (2^30 - 1 because 0 is UNSET). */