/** Given a key, returns the index of the entry in the tables, or ABSENT if not found. */
  private int findEntryByKey(@Nullable Object key) {
    return findEntryByKey(key, Hashing.smearedHash(key));
  }

  /**
   * Given a key and its hash, returns the index of the entry in the tables, or ABSENT if not found.
   */
  private int findEntryByKey(@Nullable Object key, int keyHash) {