docs: public static String toStringLow(long[] v) {
      if(v == null) {
        return "null";
      }
      final int mag = magnitude(v);
      if(mag == 0) {
        return "0";
      }
      char[] digits = new char[mag];
      int pos = 0;
  
      outer: for(int w = 0; w < v.length; w++) {
        long f = 1L;
        for(int i = 0; i < Long.SIZE; i++) {
          digits[pos] = ((v[w] & f) == 0) ? '0' : '1';
          f <<= 1;
          ++pos;
          if(pos >= mag) {
            break outer;
          }
        }
      }
      for(; pos < mag; ++pos) {
        digits[pos] = '0';
      }
      return new String(digits);
    }