Function actix_service::apply_cfg_factory

pub fn apply_cfg_factory<F, C, T, R, S>(
    factory: T, 
    f: F
) -> impl ServiceFactory<Config = C, Request = S::Request, Response = S::Response, Error = S::Error, Service = S, InitError = T::InitError> + Clone where
    F: FnMut(C, &mut T::Service) -> R,
    T: ServiceFactory<Config = ()>,
    T::InitError: From<T::Error>,
    R: Future<Output = Result<S, T::InitError>>,
    S: Service, 

Convert Fn(Config, &mut Service1) -> Future<Service2> fn to a service factory

Service1 get constructed from T factory.