docs: private void validateXmlHeaderFragment(String receivedHeaderData, String controlHeaderData,
              XmlMessageValidationContext validationContext, TestContext context) {
          log.debug("Start XML header data validation ...");
  
          Document received = XMLUtils.parseMessagePayload(receivedHeaderData);
          Document source = XMLUtils.parseMessagePayload(controlHeaderData);
  
          XMLUtils.stripWhitespaceNodes(received);
          XMLUtils.stripWhitespaceNodes(source);
  
          if (log.isDebugEnabled()) {
              log.debug("Received header data:\n" + XMLUtils.serialize(received));
              log.debug("Control header data:\n" + XMLUtils.serialize(source));
          }
  
          validateXmlTree(received, source, validationContext, 
                  namespaceContextBuilder.buildContext(new DefaultMessage(receivedHeaderData), validationContext.getNamespaces()),
                  context);
      }