diff --git a/__network/async-speed-limit/Cargo.lock b/__network/async-speed-limit/Cargo.lock
new file mode 100644
index 0000000..43918e9
--- /dev/null
+++ b/__network/async-speed-limit/Cargo.lock
@@ -0,0 +1,155 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
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diff --git a/__network/async-speed-limit/Cargo.toml b/__network/async-speed-limit/Cargo.toml
new file mode 100644
index 0000000..2cd72ea
--- /dev/null
+++ b/__network/async-speed-limit/Cargo.toml
@@ -0,0 +1,12 @@
+[package]
+name = "async-speed-limit"
+version = "0.1.0"
+authors = ["Hatter Jiang <jht5945@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+async-speed-limit = "0.3.1"
+futures-util = { version = "0.3.12", features= ["io"] }
+
diff --git a/__network/async-speed-limit/README.md b/__network/async-speed-limit/README.md
new file mode 100644
index 0000000..3173d21
--- /dev/null
+++ b/__network/async-speed-limit/README.md
@@ -0,0 +1,5 @@
+
+From:
+https://github.com/tikv/async-speed-limit
+
+
diff --git a/__network/async-speed-limit/src/main.rs b/__network/async-speed-limit/src/main.rs
new file mode 100644
index 0000000..e5d3850
--- /dev/null
+++ b/__network/async-speed-limit/src/main.rs
@@ -0,0 +1,30 @@
+use async_speed_limit::Limiter;
+use futures_util::{
+    future::try_join,
+    io::{self, AsyncRead, AsyncWrite},
+};
+use std::marker::Unpin;
+
+fn main() {
+    println!("Hello, world!");
+}
+
+#[warn(dead_code)]
+async fn copy_both_slowly(
+    r1: impl AsyncRead,
+    w1: &mut (impl AsyncWrite + Unpin),
+    r2: impl AsyncRead,
+    w2: &mut (impl AsyncWrite + Unpin),
+) -> io::Result<()> {
+    // create a speed limiter of 1.0 KiB/s.
+    let limiter = <Limiter>::new(1024.0);
+
+    // limit both readers by the same queue
+    // (so 1.0 KiB/s is the combined maximum speed)
+    let r1 = limiter.clone().limit(r1);
+    let r2 = limiter.limit(r2);
+
+    // do the copy.
+    try_join(io::copy(r1, w1), io::copy(r2, w2)).await?;
+    Ok(())
+}