System.Xml.XmlDictionaryWriter.WriteQualifiedName C# (CSharp) Method

        public virtual void WriteQualifiedName(XmlDictionaryString localName, XmlDictionaryString namespaceUri)
        {
            if (localName == null)
                throw System.Runtime.Serialization.DiagnosticUtility.ExceptionUtility.ThrowHelperError(new ArgumentNullException(nameof(localName)));
            if (namespaceUri == null)
                namespaceUri = XmlDictionaryString.Empty;
#pragma warning suppress 56506 // Microsoft, XmlDictionaryString.Empty is never null
            WriteQualifiedName(localName.Value, namespaceUri.Value);
        }

 protected override void OnWriteStartHeader(XmlDictionaryWriter writer, MessageVersion messageVersion)
 {
     writer.WriteStartElement(this.Name, this.Namespace);
     writer.WriteXmlnsAttribute(null, _notUnderstoodNs);
     writer.WriteStartAttribute(Message12Strings.QName);
     writer.WriteQualifiedName(_notUnderstoodName, _notUnderstoodNs);
     writer.WriteEndAttribute();
 }