Run asynchronous interaction to ask the user for a certificate to use with the connection.
In general, invoke_request_certificate should be used instead of this function.
Derived subclasses usually implement a certificate selector, although they may also choose to provide a certificate from elsewhere.
callback will be called when the operation completes. Alternatively the user may abort this certificate request, which will
usually abort the TLS connection.
| this |
a TlsInteraction object |
| connection |
a TlsConnection object |
| flags |
flags providing more information about the request |
| cancellable |
an optional Cancellable cancellation object |
| callback |
will be called when the interaction completes |
| user_data |
data to pass to the |