code: void appendComment(int m_char_current_start,int contentLength)
    {
      // create a Comment Node
      // %TBD% may be possible to combine with appendNode()to replace the next chunk of code
      int w0 = COMMENT_NODE;
      // W1: Parent
      int w1 = currentParent;
      // W2: Start position within m_char
      int w2 = m_char_current_start;
      // W3: Length of the full string
      int w3 = contentLength;
  
      int ourslot = appendNode(w0, w1, w2, w3);
      previousSibling = ourslot;
    }
docs: Append a comment child at the current insertion point. Assumes that the
  actual content of the comment has previously been appended to the m_char
  buffer (shared with the builder).
  
  @param m_char_current_start int Starting offset of node's content in m_char.
  @param contentLength int Length of node's content in m_char.