private static Step<HttpObject> expectJsonSeqContents(Object publisherOrStream,
                                                          ResponseHeaders headers,
                                                          HttpHeaders trailers) throws Exception {
        final HttpResponse response =
                function.convertResponse(ctx, headers, publisherOrStream, trailers);
        return StepVerifier.create(response)
                           .expectNext(headers)
                           .expectNext(EXPECTED_CONTENTS[0])
                           .expectNext(EXPECTED_CONTENTS[1])
                           .expectNext(EXPECTED_CONTENTS[2])
                           .expectNext(EXPECTED_CONTENTS[3]);
    }
{@link HttpData} instances which are expected to be produced by the
{@link JacksonResponseConverterFunction} when the function gets the
{@link #TEST_STRINGS} as input.
core/src/test/java/com/linecorp/armeria/server/annotation/JacksonResponseConverterFunctionTest.java