This one adds a separate new case that has to be parsed differently - if
a hello-retry-request is sent, only the namedgroup is sent - without the
additional key material.
Support for the legacy extension is retained.
This exposes the record layer version of the fragment in addition to the
content type and the length. The ordering of the arguments in the event
is the same as the ordering in the protocol message (first type, then
version, then length).
This also includes a slight change to the analyzer, no longer calling
the generate function if the event is not used.
