code: private static Set<HttpMethod> toHttpMethods(Set<Annotation> annotations) {
          return annotations.stream()
                            .map(annotation -> HTTP_METHOD_MAP.get(annotation.annotationType()))
                            .filter(Objects::nonNull)
                            .collect(toImmutableEnumSet());
      }
docs: Returns {@link Set} of {@link HttpMethod}s mapped to HTTP method annotations.
  
  @see Options
  @see Get
  @see Head
  @see Post
  @see Put
  @see Patch
  @see Delete
  @see Trace