private void saveDrId(long drId) {
      // If the drId is <= 255 (max unsigned byte) then
      // encode it as a single byte.
      // Otherwise write a byte whose value is the number of bytes
      // it will be encoded by and then follow it with that many bytes.
      // Note that drId are not allowed to have a value in the range 1..8
      // inclusive.
      if (drId >= 0 && drId <= 255) {
        drIdLength = 1;
        drIdBytes[0] = (byte) drId;
      } else {
        byte bytesNeeded = bytesNeeded(drId);
        drIdLength = bytesNeeded + 1;
        drIdBytes[0] = bytesNeeded;
        for (int i = bytesNeeded; i >= 1; i--) {
          drIdBytes[i] = (byte) (drId & 0xFF);
          drId >>= 8;
        }
      }
      size += drIdLength;
    }
How many bytes it will be when serialized
geode-core/src/main/java/org/apache/geode/internal/cache/Oplog.java