docs: public static int lenVarUInt(long longVal) {
          assert longVal >= 0;
          if (longVal < (1L << (7 * 1))) return 1;  // 7  bits
          if (longVal < (1L << (7 * 2))) return 2;  // 14 bits
          if (longVal < (1L << (7 * 3))) return 3;  // 21 bits
          if (longVal < (1L << (7 * 4))) return 4;  // 28 bits
          if (longVal < (1L << (7 * 5))) return 5;  // 35 bits
          if (longVal < (1L << (7 * 6))) return 6;  // 42 bits
          if (longVal < (1L << (7 * 7))) return 7;  // 49 bits
          if (longVal < (1L << (7 * 8))) return 8;  // 56 bits
          if (longVal < (1L << (7 * 9))) return 9;  // 63 bits
          return 10;
      }