pub trait PrepareCall: KvarnSendSync {
    // Required method
    fn call<'a>(
        &'a self,
        request: &'a mut FatRequest,
        host: &'a Host,
        path: Option<&'a Path>,
        addr: SocketAddr,
    ) -> RetFut<'a, FatResponse>;
}Expand description
Implement this to pass your extension to Extensions::add_prepare_fn or
Extensions::add_prepare_single.