checkVersionsOrder(c, d);
        checkVersionsOrder(b, d);
        checkVersionsOrder(a, d);
    }

    /**
     * Test all versions are equal when starting with many leading zeroes regardless of string length
     * (related to MNG-6572 optimization)
     */
    @Test
    void testVersionEqualWithLeadingZeroes() {
        // versions with string lengths from 1 to 19

            + "\u1c40\u1c50\ua620\ua8d0\ua900\ua9d0\ua9f0\uaa50\uabf0\uff10";

    private static char[] zeroes() {
      return ZEROES.toCharArray();
    }

    private static char[] nines() {
      char[] nines = new char[ZEROES.length()];
      for (int i = 0; i < ZEROES.length(); i++) {
        nines[i] = (char) (ZEROES.charAt(i) + 9);
      }
      return nines;
    }

        int end = ipString.indexOf(IPV6_DELIMITER, start);
        if (end == -1) {
          end = ipString.length();
        }
        if (ipString.charAt(start) == IPV6_DELIMITER) {
          // expand zeroes
          for (int i = 0; i < partsSkipped; i++) {
            rawBytes.putShort((short) 0);
          }

        } else {
          rawBytes.putShort(parseHextet(ipString, start, end));
        }

              });
      assertEquals("Counts not as expected", Ints.asList(deltas), actualCounts);
    } finally {
      pool.shutdownNow();
    }

    // Since we have access to the backing map, verify that there are no zeroes in the map
    for (AtomicInteger value : map.values()) {
      assertTrue("map should not contain a zero", value.get() != 0);
    }
  }

  private static class MutateTask implements Callable<int[]> {

        int end = ipString.indexOf(IPV6_DELIMITER, start);
        if (end == -1) {
          end = ipString.length();
        }
        if (ipString.charAt(start) == IPV6_DELIMITER) {
          // expand zeroes
          for (int i = 0; i < partsSkipped; i++) {
            rawBytes.putShort((short) 0);
          }

        } else {
          rawBytes.putShort(parseHextet(ipString, start, end));
        }

    // Delegates to the fast (unsafe) version or the fallback.
    return byteArray.getLongLittleEndian(input, offset);
  }

  /**
   * Similar to load64, but allows offset + 8 > input.length, padding the result with zeroes. This
   * has to explicitly reverse the order of the bytes as it packs them into the result which makes
   * it slower than the native version.
   *
   * @param input the input bytes

        longestRunOffset = currentRunOffset
        longestRunLength = currentRunLength
      }
      i += 2
    }
  }

  // Emit each 2-byte group in hex, separated by ':'. The longest run of zeroes is "::".
  val result = Buffer()
  var i = 0
  while (i < address.size) {
    if (i == longestRunOffset) {
      result.writeByte(':'.code)
      i += longestRunLength

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary

   * it is returned directly. Otherwise, a new array of size {@code minLength + padding} is
   * returned, containing the values of {@code array}, and zeroes in the remaining places.
   *
   * @param array the source array
   * @param minLength the minimum length the returned array must guarantee
   * @param padding an extra amount to "grow" the array by if growth is necessary

   * AtomicInteger's atomic operations, with some help from ConcurrentMap's atomic operations on
   * creation and removal (including automatic removal of zeroes). If the modification of an
   * AtomicInteger results in zero, we compareAndSet the value to zero; if that succeeds, we remove
   * the entry from the Map. If another operation sees a zero in the map, it knows that the entry is