@Override
    public Object unmarshal(Exchange exchange, InputStream stream) throws Exception {
        return builder.build(stream);
    }
@Test
    public void testUnmarshal() throws Exception {
        InputStream stream = IOConverter.toInputStream(new File("src/test/resources/data.ics"));
        MockEndpoint endpoint = getMockEndpoint("mock:result");

        endpoint.expectedBodiesReceived(createTestCalendar());

        template.sendBody("direct:unmarshal", stream);

        endpoint.assertIsSatisfied();
    }