=head2 C<protocol_version>
The version of the protocol that the stream is currently conforming to.
+It is reset before and after the parsing phase, so it's effectively only available from inside L</parse>.
=cut
sub parse {
my ($self, $sess, $fh) = @_;
+ $self->protocol_version(undef);
+
$self->XML::Twig::parse($fh);
$self->purge;
+ $self->protocol_version(undef);
+
return;
}