private static Set<Annotation> httpMethodAnnotations(Method method) {
        return AnnotationUtil.getAnnotations(method, FindOption.LOOKUP_SUPER_CLASSES)
                             .stream()
                             .filter(annotation -> HTTP_METHOD_MAP.containsKey(annotation.annotationType()))
                             .collect(Collectors.toSet());
    }
Returns {@link Set} of HTTP method annotations of a given method.
The annotations are as follows.

@see Options
@see Get
@see Head
@see Post
@see Put
@see Patch
@see Delete
@see Trace
core/src/main/java/com/linecorp/armeria/internal/server/annotation/AnnotatedServiceFactory.java