Make the certificate and peer-certificate properties virtual, and add
peer-certificate-errors as well. Change the documentation on
peer-certificate to say that it's not set until after the handshake
succeeds (which means notify::peer-certificate can be used to tell
when a handshake has completed).
Trying to do this as a signal won't work well with either
GTlsCertificateDB (in which case looking up a certificate in the db is
a blocking/asynchronous act) or session resumption support (in which
case the certificate or lack thereof is part of the session definition
and so needs to be known immediately). Make the caller use
g_tls_connection_set_certificate() ahead of time (or when retrying)
instead.
This adds an extension point for TLS connections to gio, with a
gnutls-based implementation in glib-networking.
Full TLS support is still a work in progress; the current API is
missing some features, and parts of it may still be changed before
2.28.
https://bugzilla.gnome.org/show_bug.cgi?id=588189
