private List<ServiceConfigSetters<?>> getServiceConfigSetters(
            @Nullable VirtualHostBuilder defaultVirtualHostBuilder) {
        final List<ServiceConfigSetters<?>> serviceConfigSetters;
        if (defaultVirtualHostBuilder != null) {
            serviceConfigSetters = ImmutableList.<ServiceConfigSetters<?>>builder()
                                                .addAll(this.serviceConfigSetters)
                                                .addAll(defaultVirtualHostBuilder.serviceConfigSetters)
                                                .build();
        } else {
            serviceConfigSetters = ImmutableList.copyOf(this.serviceConfigSetters);
        }
        return serviceConfigSetters;
    }
Returns a new instance of {@link VirtualHostAnnotatedServiceBindingBuilder} to build
an annotated service fluently.
core/src/main/java/com/linecorp/armeria/server/VirtualHostBuilder.java