certificate will be installed into B<ssl>, see the NOTES and BUGS sections.
If no certificate should be set, "0" has to be returned and no certificate
will be sent. A negative return value will suspend the handshake and the
-handshake function will return immediatly. L<SSL_get_error(3)|SSL_get_error(3)>
+handshake function will return immediately. L<SSL_get_error(3)|SSL_get_error(3)>
will return SSL_ERROR_WANT_X509_LOOKUP to indicate, that the handshake was
suspended. The next call to the handshake function will again lead to the call
of client_cert_cb(). It is the job of the client_cert_cb() to store information