}
    return total;
  }

  /** Max array length on JVM. */
  private static final int MAX_ARRAY_LEN = Integer.MAX_VALUE - 8;

  /** Large enough to never need to expand, given the geometric progression of buffer sizes. */
  private static final int TO_BYTE_ARRAY_DEQUE_SIZE = 20;

  /**
   * Returns a byte array containing the bytes from the buffers already in {@code bufs} (which have

     *
     * a) every iteration (except potentially the first) has guess >= floor(sqrt(x)). This is
     * because guess' is the arithmetic mean of guess and x / guess, sqrt(x) is the geometric mean,
     * and the arithmetic mean is always higher than the geometric mean.
     *
     * b) this iteration converges to floor(sqrt(x)). In fact, the number of correct digits doubles