@Nullable
    public static SSLSession findSslSession(@Nullable Channel channel) {
        if (channel == null) {
            return null;
        }

        final SslHandler sslHandler = channel.pipeline().get(SslHandler.class);
        return sslHandler != null ? sslHandler.engine().getSession() : null;
    }
Finds the {@link SSLSession} of the current TLS connection.

@return the {@link SSLSession} if found, or {@code null} if not found or {@link Channel} is {@code null}.
core/src/main/java/com/linecorp/armeria/internal/common/util/ChannelUtil.java