diff --git a/http/src/h1/body.rs b/http/src/h1/body.rs
index cd4016a3..f0e5585c 100644
--- a/http/src/h1/body.rs
+++ b/http/src/h1/body.rs
@@ -1,6 +1,6 @@
 use core::{
     cell::{RefCell, RefMut},
-    future::{Future, poll_fn},
+    future::poll_fn,
     ops::DerefMut,
     pin::Pin,
     task::{Context, Poll, Waker},
diff --git a/http/src/h1/dispatcher.rs b/http/src/h1/dispatcher.rs
index da47bd45..b477b100 100644
--- a/http/src/h1/dispatcher.rs
+++ b/http/src/h1/dispatcher.rs
@@ -1,6 +1,6 @@
 use core::{
     convert::Infallible,
-    future::{Future, pending, poll_fn},
+    future::{pending, poll_fn},
     marker::PhantomData,
     net::SocketAddr,
     pin::{Pin, pin},
diff --git a/http/src/h1/dispatcher_uring.rs b/http/src/h1/dispatcher_uring.rs
index 2825da9e..7a305679 100644
--- a/http/src/h1/dispatcher_uring.rs
+++ b/http/src/h1/dispatcher_uring.rs
@@ -1,7 +1,7 @@
 use core::{
     cell::RefCell,
     fmt,
-    future::{Future, poll_fn},
+    future::poll_fn,
     marker::PhantomData,
     mem,
     net::SocketAddr,
diff --git a/http/src/tls/native_tls.rs b/http/src/tls/native_tls.rs
index 056253da..177dc74d 100644
--- a/http/src/tls/native_tls.rs
+++ b/http/src/tls/native_tls.rs
@@ -3,7 +3,6 @@ pub(crate) use native_tls::TlsAcceptor;
 use core::{
     convert::Infallible,
     fmt,
-    future::Future,
     pin::Pin,
     task::{Context, Poll},
 };
diff --git a/http/src/util/futures.rs b/http/src/util/futures.rs
index 5bfe864c..1f87b713 100644
--- a/http/src/util/futures.rs
+++ b/http/src/util/futures.rs
@@ -3,8 +3,6 @@ pub(crate) use queue::*;
 
 #[cfg(any(feature = "http2", feature = "http3"))]
 mod queue {
-    use core::future::Future;
-
     use futures_util::stream::{FuturesUnordered, StreamExt};
 
     pub(crate) struct Queue<F>(FuturesUnordered<F>);
diff --git a/http/src/util/middleware/context.rs b/http/src/util/middleware/context.rs
index 0a160a4e..68806599 100644
--- a/http/src/util/middleware/context.rs
+++ b/http/src/util/middleware/context.rs
@@ -1,6 +1,6 @@
 //! middleware for adding typed state to service request.
 
-use core::{fmt, future::Future};
+use core::fmt;
 
 use xitca_service::Service;
 
diff --git a/http/src/util/service/handler.rs b/http/src/util/service/handler.rs
index 9d937290..38c3a837 100644
--- a/http/src/util/service/handler.rs
+++ b/http/src/util/service/handler.rs
@@ -2,7 +2,7 @@
 
 #![allow(non_snake_case)]
 
-use core::{convert::Infallible, future::Future, marker::PhantomData, net::SocketAddr};
+use core::{convert::Infallible, marker::PhantomData, net::SocketAddr};
 
 use xitca_service::{Service, pipeline::PipelineE};
 
diff --git a/http/src/util/service/router.rs b/http/src/util/service/router.rs
index 394154d9..cff6b081 100644
--- a/http/src/util/service/router.rs
+++ b/http/src/util/service/router.rs
@@ -21,7 +21,7 @@ pub use self::object::RouteObject;
 /// in order to determine how the router type-erases node services.
 pub struct Router<Obj> {
     // record for last time PathGen is called with certain route string prefix.
-    prefix: Option<usize>,
+    prefix: usize,
     routes: HashMap<String, Obj>,
 }
 
@@ -34,7 +34,7 @@ impl<Obj> Default for Router<Obj> {
 impl<Obj> Router<Obj> {
     pub fn new() -> Self {
         Router {
-            prefix: None,
+            prefix: 0,
             routes: HashMap::new(),
         }
     }
@@ -183,8 +183,7 @@ where
             path.pop();
         }
 
-        let prefix = self.prefix.get_or_insert(0);
-        *prefix += path.len();
+        self.prefix += path.len();
 
         self.routes.iter_mut().for_each(|(_, v)| {
             v.path_gen(path.as_str());
@@ -436,7 +435,7 @@ mod service {
     pub struct RouterService<S> {
         // a length record of prefix of current router.
         // when it's Some the request path has to be sliced to exclude the string path prefix.
-        pub(super) prefix: Option<usize>,
+        pub(super) prefix: usize,
         pub(super) router: xitca_router::Router<S>,
     }
 
@@ -452,15 +451,11 @@ mod service {
         // using async fn call directly would cause significant code bloating.
         #[allow(clippy::manual_async_fn)]
         #[inline]
-        fn call(&self, mut req: Req) -> impl core::future::Future<Output = Result<Self::Response, Self::Error>> {
+        fn call(&self, mut req: Req) -> impl Future<Output = Result<Self::Response, Self::Error>> {
             async {
-                let mut path = req.borrow().path();
-
-                if let Some(prefix) = self.prefix {
-                    path = &path[prefix..];
-                }
-
-                let xitca_router::Match { value, params } = self.router.at(path).map_err(RouterError::Match)?;
+                let path = req.borrow().path();
+                let xitca_router::Match { value, params } =
+                    self.router.at(&path[self.prefix..]).map_err(RouterError::Match)?;
                 *req.borrow_mut() = params;
                 Service::call(value, req).await
             }
diff --git a/http/src/util/timer.rs b/http/src/util/timer.rs
index b9af89af..1153f5cb 100644
--- a/http/src/util/timer.rs
+++ b/http/src/util/timer.rs
@@ -1,5 +1,4 @@
-use std::{
-    future::Future,
+use core::{
     pin::Pin,
     task::{Context, Poll, ready},
 };