diff --git a/README.md b/README.md
index d31024d..5ff7af5 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@
 
 * Minimal and Efficient : minimal codebase to provide efficient, memory-safe WebSocket handling.
 
-* Multi Environment : `tokio`, `smol`, `glommio` are supported as async runtime ( by feature flags `rt_{name}` ).
+* Multi-Environment : `tokio`, `smol`, `glommio` are supported as async runtime ( by feature flags `rt_{name}` ).
 
 ## Note
 
@@ -33,10 +33,11 @@ mews  = { version = "0.2", features = ["rt_tokio"] }
 tokio = { version = "1",   features = ["rt"] }
 # ...
 ```
-*( with pseudo Request & Response )*
-```rust
+**( with pseudo Request & Response )**
+```rust,ignore
 /* server */
 
+use tokio::net::TcpStream;
 use mews::{WebSocketContext, Connection, Message};
 
 async fn handle_websocket(
@@ -48,7 +49,7 @@ async fn handle_websocket(
     );
 
     let (sign, ws) = ctx.on_upgrade(
-        |mut conn: Connection| async move {
+        |mut conn: Connection<TcpStream>| async move {
             while let Ok(Some(Message::Text(text))) = conn.recv().await {
                 conn.send(text).await
                     .expect("failed to send message");
@@ -67,9 +68,11 @@ async fn handle_websocket(
     ws.manage(tcp);
 }
 ```
-```rust
+```rust,ignore
 /* client */
 
+use tokio::net::TcpStream;
+
 async fn start_websocket(
     mut tcp: TcpStream
 ) {
@@ -80,7 +83,7 @@ async fn start_websocket(
     );
 
     let (sign, ws) = ctx.on_upgrade(
-        |mut conn: Connection| async move {
+        |mut conn: Connection<TcpStream>| async move {
             conn.send("Hello!").await.expect("failed to send message");
             while let Ok(Some(Message::Text(text))) = conn.recv().await {
                 println!("got: `{text}`")
diff --git a/src/connection.rs b/src/connection.rs
index 0101eb8..82ef8a4 100644
--- a/src/connection.rs
+++ b/src/connection.rs
@@ -5,7 +5,7 @@ use std::{sync::Arc, io::Error};
 pub trait UnderlyingConnection: AsyncRead + AsyncWrite + Unpin + 'static {}
 impl<T: AsyncRead + AsyncWrite + Unpin + 'static> UnderlyingConnection for T {}
 
-pub struct Connection<C: UnderlyingConnection = crate::runtime::TcpStream> {
+pub struct Connection<C: UnderlyingConnection> {
     __closed__: Arc<RwLock<bool>>,
 
     conn: Arc<std::cell::UnsafeCell<C>>,
@@ -343,14 +343,6 @@ pub mod split {
                 <tokio::net::TcpStream>::split(self)
             }
         }
-        #[cfg(feature="rt_nio")]
-        impl<'split> Splitable<'split> for nio::net::TcpStream {
-            type ReadHalf  = nio::net::tcp::ReadHalf <'split>;
-            type WriteHalf = nio::net::tcp::WriteHalf<'split>;
-            fn split(&'split mut self) -> (Self::ReadHalf, Self::WriteHalf) {
-                <nio::net::TcpStream>::split(self)
-            }
-        }
         #[cfg(feature="rt_glommio")]
         impl<'split, T: AsyncRead + AsyncWrite + Unpin + 'split> Splitable<'split> for T {
             type ReadHalf  = futures_util::io::ReadHalf <&'split mut T>;
@@ -371,7 +363,7 @@ pub mod split {
         }
     };
 
-    pub struct ReadHalf<C: AsyncRead + Unpin = <crate::runtime::TcpStream as Splitable<'static>>::ReadHalf> {
+    pub struct ReadHalf<C: AsyncRead + Unpin> {
         __closed__: Arc<RwLock<bool>>,
         conn:   C,
         config: Config,
@@ -389,7 +381,7 @@ pub mod split {
         }
     }
 
-    pub struct WriteHalf<C: AsyncWrite + Unpin = <crate::runtime::TcpStream as Splitable<'static>>::WriteHalf> {
+    pub struct WriteHalf<C: AsyncWrite + Unpin> {
         __closed__: Arc<RwLock<bool>>,
         conn:       C,
         config:     Config,
diff --git a/src/lib.rs b/src/lib.rs
index 64e9f40..b55a599 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -36,7 +36,6 @@ compile_error! {"More than one runtime feature flags can't be activated"}
 mod runtime {
     #[cfg(feature="rt_tokio")]
     pub use {
-        tokio::net::TcpStream,
         tokio::io::AsyncReadExt as AsyncRead,
         tokio::io::AsyncWriteExt as AsyncWrite,
         tokio::sync::RwLock,
@@ -45,7 +44,6 @@ mod runtime {
 
     #[cfg(feature="rt_smol")]
     pub use {
-        smol::net::TcpStream,
         smol::io::AsyncReadExt as AsyncRead,
         smol::io::AsyncWriteExt as AsyncWrite,
         smol::lock::RwLock,
@@ -57,7 +55,6 @@ mod runtime {
 
     #[cfg(feature="rt_glommio")]
     pub use {
-        glommio::net::TcpStream,
         futures_util::AsyncReadExt as AsyncRead,
         futures_util::AsyncWriteExt as AsyncWrite,
         glommio::sync::RwLock,
diff --git a/src/websocket.rs b/src/websocket.rs
index 5fd246b..406c4db 100644
--- a/src/websocket.rs
+++ b/src/websocket.rs
@@ -1,4 +1,3 @@
-use crate::runtime;
 use crate::message::{CloseFrame, CloseCode};
 use crate::connection::{UnderlyingConnection, Connection};
 
@@ -47,7 +46,7 @@ pub type Handler<C> = Box<dyn
 ///     );
 /// 
 ///     let (sign, ws) = ctx.on_upgrade(
-///         |mut conn: Connection| async move {
+///         |mut conn: Connection<TcpStream>| async move {
 ///             while let Ok(Some(Message::Text(text))) = conn.recv().await {
 ///                 conn.send(text).await
 ///                     .expect("failed to send message");
@@ -130,7 +129,7 @@ const _: () = {
 ///     tcp: TcpStream
 /// ) -> Response {
 ///     let (sign, ws) = ctx.on_upgrade(
-///         |mut conn: Connection| async move {
+///         |mut conn: Connection<TcpStream>| async move {
 ///             while let Ok(Some(Message::Text(text))) = conn.recv().await {
 ///                 conn.send(text).await
 ///                     .expect("failed to send message");
@@ -145,7 +144,7 @@ const _: () = {
 /// }
 /// ```
 #[must_use = "`WebSocket` does nothing unless `.manage()` or `.manage_with_timeout()` is called"]
-pub struct WebSocket<C: UnderlyingConnection = runtime::TcpStream> {
+pub struct WebSocket<C: UnderlyingConnection> {
     config:  Config,
     handler: Handler<C>,
 }
@@ -185,7 +184,7 @@ impl<C: UnderlyingConnection> WebSocket<C> {
 const _: () = {
     impl<C: UnderlyingConnection> PartialEq for WebSocket<C>
     where
-        dyn FnOnce(Connection<C>) -> std::pin::Pin<Box<(dyn std::future::Future<Output = ()> + Send + 'static)>> + Send + Sync
+        dyn FnOnce(Connection<C>) -> std::pin::Pin<Box<dyn std::future::Future<Output = ()> + Send + 'static>> + Send + Sync
         : PartialEq
     {
         fn eq(&self, other: &Self) -> bool {