Add preSharedKeyIdentity to the ServerHandshaker.

[boaks]

Support creating statistics.

Signed-off-by: Achim Kraus achim.kraus@bosch-si.com

[boaks]

Second part of the fix for #744

[boaks]

Alternatively, the already available clientKeyExchange could be exposed public.
Then check for specific subclass PSKClientKeyExchange and read the identifier there.

@sbernard31
If you can give us your feedback of your preferred variant,
FMPOV, we could finalize the work for the 2.0.0-M12 and release that next week.

[sbernard31]

I have no strong opinion about that.
Maybe the clientKeyExchange way is more flexible has we can access to more data than just the PSKIdentity ? But this is not a strong argument so I'm ok with the current implementation too.

[boaks]

So, go for this.