void onPeerCertificateAvailable(String peerHost, int peerPort) throws CertificateException {
        synchronized (ssl) {
            id = null;
            if (localCertificates == null) {
                this.localCertificates = ssl.getLocalCertificates();
            }
            if (this.peerCertificates == null) {
                // When resuming a session, the cert_verify_callback (which calls
                // onPeerCertificatesReceived) isn't called by BoringSSL during the handshake
                // because it presumes the certs were verified in the previous connection on that
                // session, leaving us without the peer certificates.  If that happens, fetch them
                // explicitly.
                configurePeer(peerHost, peerPort, ssl.getPeerCertificates());
            }
        }
    }
Updates the cached peer certificate after the handshake has completed
(or entered False Start).
common/src/main/java/org/conscrypt/ActiveSession.java