private static HttpHeaders responseTrailers(Method method, Class<?> clazz, String classAlias,
                                                String methodAlias) {
        final HttpHeadersBuilder defaultTrailers = HttpHeaders.builder();
        setAdditionalHeader(defaultTrailers, clazz, "trailer", classAlias, "class",
                            AdditionalTrailer.class, AdditionalTrailer::name, AdditionalTrailer::value);
        setAdditionalHeader(defaultTrailers, method, "trailer", methodAlias, "method",
                            AdditionalTrailer.class, AdditionalTrailer::name, AdditionalTrailer::value);
        return defaultTrailers.build();
    }
Returns a list of {@link AnnotatedService} instances. A single {@link AnnotatedService} is
created per each {@link Route} associated with the {@code method}.
core/src/main/java/com/linecorp/armeria/internal/server/annotation/AnnotatedServiceFactory.java