presto-client/src/main/java/io/prestosql/client/SpnegoHandler.java/SpnegoHandler/intercept
class SpnegoHandler:    @Override
    public Response intercept(Chain chain)
            throws IOException
    {
        // eagerly send authentication if possible
        try {
            return chain.proceed(authenticate(chain.request()));
        }
        catch (ClientException ignored) {
            return chain.proceed(chain.request());
        }
    }