public Variant externalize ()
Build an externalized form of this which can be used together with parse_external to rebuild a copy of this.
It is important to note that the variant returned from this method does not have the same type signature as returned from a call to serialize. Externalization will wrap the serialized data in a container format with versioning information and headers with type information.
The instance to externalize
A floating reference to a Variant with the externalized data.