docs: public boolean add(final int value)
      {
          if (value == MISSING_VALUE)
          {
              final boolean previousContainsMissingValue = this.containsMissingValue;
              containsMissingValue = true;
              return !previousContainsMissingValue;
          }
  
          final int[] values = this.values;
          @DoNotSub final int mask = values.length - 1;
          @DoNotSub int index = Hashing.hash(value, mask);
  
          while (values[index] != MISSING_VALUE)
          {
              if (values[index] == value)
              {
                  return false;
              }
  
              index = next(index, mask);
          }
  
          values[index] = value;
          sizeOfArrayValues++;
  
          if (sizeOfArrayValues > resizeThreshold)
          {
              increaseCapacity();
          }
  
          return true;
      }