docs: @Override
      public String toXML(org.jivesoftware.smack.packet.XmlEnvironment enclosingNamespace) {
          StringBuilder buf = new StringBuilder();
  
          synchronized (payloads) {
              if (payloads.size() > 0) {
                  buf.append('<').append(getElementName());
                  buf.append(" xmlns=\"").append(getNamespace()).append("\" >");
  
                  Iterator<JinglePayloadType> pt = payloads.listIterator();
                  while (pt.hasNext()) {
                      JinglePayloadType pte = pt.next();
                      buf.append(pte.toXML());
                  }
                  buf.append("</").append(getElementName()).append('>');
              }
          }
  
          return buf.toString();
      }