docs: public Integer getBlockMaskPrefixLength(boolean network) {
  		int hostLength = getTrailingBitCount(network);
  		long shifted;
  		if(network) {
  			shifted = (~getDivisionValue() & getMaxValue())  >>> hostLength;
  		} else {
  			shifted = getDivisionValue() >>> hostLength;
  		}
  		return shifted == 0 ? getBitCount() - hostLength : null;
  	}