public Set<DescriptiveTypeSignature> findDescriptiveTypes() {
        final Set<DescriptiveTypeSignature> requestDescriptiveTypes = findDescriptiveTypes(true);
        final Set<DescriptiveTypeSignature> responseDescriptiveType = findDescriptiveTypes(false);
        final int estimatedSize = requestDescriptiveTypes.size() + responseDescriptiveType.size();
        return ImmutableSet.<DescriptiveTypeSignature>builderWithExpectedSize(estimatedSize)
                           .addAll(requestDescriptiveTypes)
                           .addAll(responseDescriptiveType)
                           .build();
    }
Returns all enum, struct and exception {@link TypeSignature}s referred to by this service.
core/src/main/java/com/linecorp/armeria/server/docs/ServiceInfo.java