docs: private void writePrefix(int type, int length)
      {
          if (length >= lnIsVarLen)
          {
              writeVarUInt(length);
              length = lnIsVarLen;
          }
  
          int offset = myOffset;
          if (--offset < 0) {
              offset = growBuffer(offset);
          }
          myBuffer[offset] = (byte) (type | length);
          myOffset = offset;
      }