+ virtual std::string ToHuman(const Extensible* container, void* item) const;
+ /** Gets an ExtensionItem's value in the internal format.
+ * @param container The container the ExtensionItem is set on.
+ * @param item The value to convert to the internal format.
+ * @return The value specified in \p item in the internal format.
+ */
+ virtual std::string ToInternal(const Extensible* container, void* item) const ;
+
+ /** Gets an ExtensionItem's value in the network format.
+ * @param container The container the ExtensionItem is set on.
+ * @param item The value to convert to the network format.
+ * @return The value specified in \p item in the network format.
+ */
+ virtual std::string ToNetwork(const Extensible* container, void* item) const;
+
+ /** Deallocates the specified ExtensionItem value.
+ * @param container The container that the ExtensionItem is set on.
+ * @param item The item to deallocate.
+ */
+ virtual void free(Extensible* container, void* item) = 0;
+
+ /** Registers this object with the ExtensionManager. */