Get the actually used cipher name,bits,version of the established connection.

get_cipher_name, get_cipher_bits, get_cipher_version methods are
wrappers for SSL_get_cipher_name, SSL_get_cipher_bits,
SSL_get_cipher_version

https://www.openssl.org/docs/ssl/SSL_get_current_cipher.html
https://www.openssl.org/docs/ssl/SSL_CIPHER_get_name.html

The low-level binding code has been merged to pyca/cryptography in:
https://github.com/pyca/cryptography/pull/649