+ /**
+ * Fetch a list of protocol extensions as raw XML.
+ *
+ * @param boolean $create Create the list if it does not already exist.
+ * @return TypedDoublyLinkedList A list of protocol extensions.
+ */
+ public function getExtensions(bool $create = true)
+ {
+ if ($create && $this->extensions === null)
+ $this->extensions = new TypedDoublyLinkedList('string');
+ return $this->extensions;
+ }
+