void log(SslHandler handler) {
  SSLEngine sslEngine = handler.engine();
    
  Future<Channel> handshakeFuture = handler.handshakeFuture();
  handshakeFuture.addListener(new MySslLogger(sslEngine));
}

class MySslLogger implements FutureListener<Channel> {
  private final SSLEngine sslEngine;

  public HandshakeListener(SSLEngine sslEngine) {
    this.sslEngine = sslEngine;
  }

  @Override
  public void operationComplete(Future<Channel> future) throws Exception {
    SSLSession sslSession = sslEngine.getSession();
    String protocol = sslSession.getProtocol();
    String cipher = sslSession.getCipherSuite();

    System.out.println("protocol=" + protocol + ", cipher=" + cipher);
  }
}