diff --git a/Cargo.toml b/Cargo.toml
index bff4600a..29484afe 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,7 +1,7 @@
 [package]
 name = "web-push"
 description = "Web push notification client with support for http-ece encryption and VAPID authentication."
-version = "0.9.1"
+version = "0.9.2"
 authors = ["Julius de Bruijn <julius+github@nauk.io>", "Andrew Ealovega <Andrew@Ealovega.dev>"]
 license = "Apache-2.0"
 homepage = "https://github.com/pimeys/rust-web-push"
@@ -10,7 +10,7 @@ documentation = "https://docs.rs/web-push/"
 readme = "README.md"
 keywords = ["web-push", "http-ece", "vapid"]
 categories = ["web-programming", "asynchronous"]
-edition = "2018"
+edition = "2021"
 
 [features]
 default = ["isahc", "futures-lite/futures-io"] #futures are only used for read_to_end() in isach client.
diff --git a/rustfmt.toml b/rustfmt.toml
index 9328e6c1..01b441c0 100644
--- a/rustfmt.toml
+++ b/rustfmt.toml
@@ -1,2 +1,2 @@
 max_width = 120
-edition = "2018"
+edition = "2021"
diff --git a/src/clients/hyper_client.rs b/src/clients/hyper_client.rs
index 5490b001..a427f015 100644
--- a/src/clients/hyper_client.rs
+++ b/src/clients/hyper_client.rs
@@ -10,7 +10,11 @@ use crate::message::WebPushMessage;
 
 /// An async client for sending the notification payload.
 ///
+/// This client is thread-safe. Clones of this client will share the same underlying resources,
+/// so cloning is a cheap and effective method to provide access to the client.
+///
 /// This client is [`hyper`](https://crates.io/crates/hyper) based, and will only work in Tokio contexts.
+#[derive(Clone)]
 pub struct WebPushClient {
     client: Client<HttpsConnector<HttpConnector>>,
 }
@@ -48,7 +52,7 @@ impl WebPushClient {
             .headers()
             .get(RETRY_AFTER)
             .and_then(|ra| ra.to_str().ok())
-            .and_then(|ra| RetryAfter::from_str(ra));
+            .and_then(RetryAfter::from_str);
 
         let response_status = response.status();
         trace!("Response status: {}", response_status);
diff --git a/src/clients/isahc_client.rs b/src/clients/isahc_client.rs
index cf494fad..467921de 100644
--- a/src/clients/isahc_client.rs
+++ b/src/clients/isahc_client.rs
@@ -9,7 +9,11 @@ use crate::message::WebPushMessage;
 /// An async client for sending the notification payload. This client is expensive to create, and
 /// should be reused.
 ///
+/// This client is thread-safe. Clones of this client will share the same underlying resources,
+/// so cloning is a cheap and effective method to provide access to the client.
+///
 /// This client is built on [`isahc`](https://crates.io/crates/isahc), and will therefore work on any async executor.
+#[derive(Clone)]
 pub struct WebPushClient {
     client: HttpClient,
 }
@@ -46,7 +50,7 @@ impl WebPushClient {
             .headers()
             .get(RETRY_AFTER)
             .and_then(|ra| ra.to_str().ok())
-            .and_then(|ra| RetryAfter::from_str(ra));
+            .and_then(RetryAfter::from_str);
 
         let response_status = response.status();
         trace!("Response status: {}", response_status);