Type Alias MiddlewareChainOld 

pub type MiddlewareChainOld<State, CTX, Request, Response, Error> = Box<dyn Fn(State, Context<CTX, Request, Response>, Option<Arc<Next<State, Context<CTX, Request, Response>, Error>>>) -> MiddlewareOutput<Context<CTX, Request, Response>, Error> + Send + Sync>;

Aliased Type

pub struct MiddlewareChainOld<State, CTX, Request, Response, Error>(/* private fields */);