@Override
    public String getPeerHost() {
        return peerHost;
    }
Returns the certificate(s) of the peer in this SSL session
used in the handshaking phase of the connection.
Please notice hat this method is superseded by
<code>getPeerCertificates()</code>.
@return an array of X509 certificates (the peer's one first and then
        eventually that of the certification authority) or null if no
        certificate were used during the SSL connection.
@throws SSLPeerUnverifiedException if either a non-X.509 certificate
        was used (i.e. Kerberos certificates) or the peer could not
        be verified.
common/src/main/java/org/conscrypt/ActiveSession.java