diff --git a/rust/sbd-bench/examples/c_count_scale.rs b/rust/sbd-bench/examples/c_count_scale.rs
new file mode 100644
index 0000000..9a4ea58
--- /dev/null
+++ b/rust/sbd-bench/examples/c_count_scale.rs
@@ -0,0 +1,4 @@
+#[tokio::main(flavor = "multi_thread")]
+async fn main() {
+    sbd_bench::c_count_scale(usize::MAX).await;
+}
diff --git a/rust/sbd-bench/src/c_count_scale.rs b/rust/sbd-bench/src/c_count_scale.rs
new file mode 100644
index 0000000..98776fb
--- /dev/null
+++ b/rust/sbd-bench/src/c_count_scale.rs
@@ -0,0 +1,166 @@
+use super::*;
+use std::sync::Mutex;
+
+pub struct Fail(Arc<tokio::sync::Semaphore>, bool);
+
+impl Clone for Fail {
+    fn clone(&self) -> Self {
+        Self(self.0.clone(), false)
+    }
+}
+
+impl Drop for Fail {
+    fn drop(&mut self) {
+        if self.1 {
+            self.0.close();
+        }
+    }
+}
+
+impl Default for Fail {
+    fn default() -> Self {
+        Self(Arc::new(tokio::sync::Semaphore::new(0)), false)
+    }
+}
+
+impl Fail {
+    fn set_fail_on_drop(&mut self, fail_on_drop: bool) {
+        self.1 = fail_on_drop;
+    }
+
+    async fn fail(&self) {
+        let _ = self.0.acquire().await;
+    }
+}
+
+struct Stats {
+    addr: std::net::SocketAddr,
+    last_ip: u32,
+    client_count: usize,
+    messages_sent: usize,
+}
+
+impl std::fmt::Debug for Stats {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Stats")
+            .field("client_count", &self.client_count)
+            .field("messages_sent", &self.messages_sent)
+            .finish()
+    }
+}
+
+async fn create_client(this: &Mutex<Stats>) -> (SbdClient, MsgRecv) {
+    let crypto = DefaultCrypto::default();
+
+    let (ip, addr) = {
+        let mut lock = this.lock().unwrap();
+        let ip = lock.last_ip;
+        lock.last_ip += 1;
+        lock.client_count += 1;
+        (ip, lock.addr)
+    };
+
+    let ip = ip.to_be_bytes();
+    let ip = std::net::Ipv4Addr::new(ip[0], ip[1], ip[2], ip[3]);
+    let ip = format!("{ip}");
+
+    let c = SbdClientConfig {
+        allow_plain_text: true,
+        headers: vec![("test-ip".to_string(), ip)],
+        ..Default::default()
+    };
+
+    let url = format!("ws://{}", addr);
+
+    SbdClient::connect_config(&url, &crypto, c).await.unwrap()
+}
+
+pub async fn c_count_scale(max: usize) -> ! {
+    let config = Arc::new(Config {
+        bind: vec!["127.0.0.1:0".to_string(), "[::1]:0".to_string()],
+        trusted_ip_header: Some("test-ip".to_string()),
+        ..Default::default()
+    });
+
+    let server = SbdServer::new(config).await.unwrap();
+
+    let addr = *server.bind_addrs().first().unwrap();
+
+    let stats = Arc::new(Mutex::new(Stats {
+        addr,
+        last_ip: u32::from_be_bytes([1, 1, 1, 1]),
+        client_count: 0,
+        messages_sent: 0,
+    }));
+
+    let fail = Fail::default();
+
+    for _ in 0..16 {
+        let stats = stats.clone();
+        let mut fail = fail.clone();
+        tokio::task::spawn(async move {
+            loop {
+                fail.set_fail_on_drop(true);
+
+                let client_count = stats.lock().unwrap().client_count;
+                if client_count > max {
+                    fail.set_fail_on_drop(false);
+
+                    return;
+                }
+
+                let (c_a, mut r_a) = create_client(&stats).await;
+                let (c_b, mut r_b) = create_client(&stats).await;
+
+                let mut fail = fail.clone();
+                let stats = stats.clone();
+                tokio::task::spawn(async move {
+                    fail.set_fail_on_drop(true);
+
+                    loop {
+                        c_a.send(c_b.pub_key(), b"hello").await.unwrap();
+                        c_b.send(c_a.pub_key(), b"world").await.unwrap();
+                        let m = r_b.recv().await?;
+                        assert_eq!(b"hello", m.message());
+                        let m = r_a.recv().await?;
+                        assert_eq!(b"world", m.message());
+
+                        stats.lock().unwrap().messages_sent += 2;
+
+                        tokio::time::sleep(std::time::Duration::from_secs(2))
+                            .await;
+                    }
+
+                    #[allow(unreachable_code)]
+                    Some(())
+                });
+            }
+        });
+    }
+
+    tokio::task::spawn(async move {
+        loop {
+            tokio::time::sleep(std::time::Duration::from_secs(3)).await;
+
+            println!("{:?}", *stats.lock().unwrap());
+        }
+    });
+
+    fail.fail().await;
+
+    panic!("test failed")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[tokio::test(flavor = "multi_thread")]
+    async fn c_count_scale_test() {
+        let _ = tokio::time::timeout(
+            std::time::Duration::from_secs(5),
+            c_count_scale(300),
+        )
+        .await;
+    }
+}
diff --git a/rust/sbd-bench/src/lib.rs b/rust/sbd-bench/src/lib.rs
index 56152a6..cf21fd0 100644
--- a/rust/sbd-bench/src/lib.rs
+++ b/rust/sbd-bench/src/lib.rs
@@ -18,6 +18,7 @@ async fn raw_connect(
             max_message_size: 1000,
             allow_plain_text: true,
             danger_disable_certificate_check: false,
+            headers: Vec::new(),
         })
         .connect()
         .await
@@ -33,3 +34,6 @@ pub use thru::*;
 
 mod c_turnover;
 pub use c_turnover::*;
+
+mod c_count_scale;
+pub use c_count_scale::*;
diff --git a/rust/sbd-client/src/lib.rs b/rust/sbd-client/src/lib.rs
index 43c74e5..fd8d50d 100644
--- a/rust/sbd-client/src/lib.rs
+++ b/rust/sbd-client/src/lib.rs
@@ -190,7 +190,7 @@ impl MsgRecv {
 }
 
 /// Configuration for connecting an SbdClient.
-#[derive(Clone, Copy)]
+#[derive(Clone)]
 pub struct SbdClientConfig {
     /// Outgoing message buffer size.
     pub out_buffer_size: usize,
@@ -202,6 +202,9 @@ pub struct SbdClientConfig {
     /// scheme. WARNING: this is a dangerous configuration and should not
     /// be used outside of testing (i.e. self-signed tls certificates).
     pub danger_disable_certificate_check: bool,
+
+    /// Set any custom http headers to send with the websocket connect.
+    pub headers: Vec<(String, String)>,
 }
 
 impl Default for SbdClientConfig {
@@ -210,6 +213,7 @@ impl Default for SbdClientConfig {
             out_buffer_size: MAX_MSG_SIZE * 8,
             allow_plain_text: false,
             danger_disable_certificate_check: false,
+            headers: Vec::new(),
         }
     }
 }
@@ -259,6 +263,7 @@ impl SbdClient {
             allow_plain_text: config.allow_plain_text,
             danger_disable_certificate_check: config
                 .danger_disable_certificate_check,
+            headers: config.headers,
         }
         .connect()
         .await?;
diff --git a/rust/sbd-client/src/raw_client.rs b/rust/sbd-client/src/raw_client.rs
index d9f5581..17db367 100644
--- a/rust/sbd-client/src/raw_client.rs
+++ b/rust/sbd-client/src/raw_client.rs
@@ -14,11 +14,13 @@ pub struct WsRawConnect {
     /// Setting this to `true` allows `ws://` scheme.
     pub allow_plain_text: bool,
 
-    #[allow(unused_variables)]
     /// Setting this to `true` disables certificate verification on `wss://`
     /// scheme. WARNING: this is a dangerous configuration and should not
     /// be used outside of testing (i.e. self-signed tls certificates).
     pub danger_disable_certificate_check: bool,
+
+    /// Set any custom http headers to send with the websocket connect.
+    pub headers: Vec<(String, String)>,
 }
 
 impl WsRawConnect {
@@ -29,9 +31,21 @@ impl WsRawConnect {
             max_message_size,
             allow_plain_text,
             danger_disable_certificate_check,
+            headers,
         } = self;
 
-        let request = tokio_tungstenite::tungstenite::client::IntoClientRequest::into_client_request(full_url).map_err(Error::other)?;
+        use tokio_tungstenite::tungstenite::client::IntoClientRequest;
+        let mut request = IntoClientRequest::into_client_request(full_url)
+            .map_err(Error::other)?;
+
+        for (k, v) in headers {
+            use tokio_tungstenite::tungstenite::http::header::*;
+            let k =
+                HeaderName::from_bytes(k.as_bytes()).map_err(Error::other)?;
+            let v =
+                HeaderValue::from_bytes(v.as_bytes()).map_err(Error::other)?;
+            request.headers_mut().insert(k, v);
+        }
 
         let scheme_ws = request.uri().scheme_str() == Some("ws");
         let scheme_wss = request.uri().scheme_str() == Some("wss");
diff --git a/rust/sbd-server/tests/rate_limit_enforced.rs b/rust/sbd-server/tests/rate_limit_enforced.rs
index 7b08531..2e1f3b8 100644
--- a/rust/sbd-server/tests/rate_limit_enforced.rs
+++ b/rust/sbd-server/tests/rate_limit_enforced.rs
@@ -18,6 +18,7 @@ async fn get_client(
             max_message_size: 100,
             allow_plain_text: true,
             danger_disable_certificate_check: false,
+            headers: Vec::new(),
         })
         .connect()
         .await