[Twisted-Python] Sending feedback on SSH authentication failures

[David Timothy Strauss]

Is there a straightforward way to send text feedback to users when
their authentication fails? At Pantheon, we use a custom
implementation of IRealm. I'm hoping there's a way to send or return
the output from there.

We particularly need this because users will have various two-factor
authentication modes configured, and a simple pass/fail for
authentication will leave many scratching their heads.

I don't see any examples of such output on the relevant documentation page [1].

[1] https://twistedmatrix.com/documents/current/core/howto/cred.html