docs: private static int outputLeadingTriplet(int triplet, char[] buffer, int offset)
      {
          int digitOffset = (triplet << 2);
          char c = LEADING_TRIPLETS[digitOffset++];
          if (c != NULL_CHAR) {
              buffer[offset++] = c;
          }
          c = LEADING_TRIPLETS[digitOffset++];
          if (c != NULL_CHAR) {
              buffer[offset++] = c;
          }
          // Last is required to be non-empty
          buffer[offset++] = LEADING_TRIPLETS[digitOffset];
          return offset;
      }