void assertSimpleDataFeedRequestContent(int expected) {
        Assertions.assertThat(dataFeedRequests).hasSize(expected);

        final List<String> expectedFiles = List.of(
                "001.dat",
                "001.meta");
        assertDataFeedRequestContent(dataFeedRequests, expectedFiles);
    }
Assert that a http header is present and has this value
stroom-proxy/stroom-proxy-app/src/test/java/stroom/proxy/app/MockHttpDestination.java