docs: public static byte[] long2buff(long n) {
          byte[] bs;
  
          bs = new byte[8];
          bs[0] = (byte) ((n >> 56) & 0xFF);
          bs[1] = (byte) ((n >> 48) & 0xFF);
          bs[2] = (byte) ((n >> 40) & 0xFF);
          bs[3] = (byte) ((n >> 32) & 0xFF);
          bs[4] = (byte) ((n >> 24) & 0xFF);
          bs[5] = (byte) ((n >> 16) & 0xFF);
          bs[6] = (byte) ((n >> 8) & 0xFF);
          bs[7] = (byte) (n & 0xFF);
  
          return bs;
      }