https://learn.microsoft.com/en-us/dotnet/api/system.configuration.configurationelement.serializetoxmlelement?view=netframework-4.8.1&redirectedfrom=MSDN
ConfigurationElement.SerializeToXmlElement(XmlWriter, String) Method (System.Configuration) |...
Writes the outer tags of this configuration element to the configuration file when implemented in a derived class.
xmlwriterstringmethodsystemconfiguration