docs: public void write(Writer writer, String enclosingNamespace) throws IOException {
          for (CharSequence csq : sb.getAsList()) {
              if (csq instanceof XmlStringBuilder) {
                  ((XmlStringBuilder) csq).write(writer, enclosingNamespace);
              }
              else if (csq instanceof XmlNsAttribute) {
                  XmlNsAttribute xmlNsAttribute = (XmlNsAttribute) csq;
                  if (!xmlNsAttribute.value.equals(enclosingNamespace)) {
                      writer.write(xmlNsAttribute.toString());
                      enclosingNamespace = xmlNsAttribute.value;
                  }
              }
              else {
                  writer.write(csq.toString());
              }
          }
      }