Always store state in an Arc (#1270)

* Add extension and state benchmarks

* wip

* Arc the state everywhere

* don't require `S: Clone`

* fix example

examples/consume-body-in-extractor-or-middleware/src/main.rs

@@ -82,7 +82,7 @@ struct PrintRequestBody;
 #[async_trait]
 impl<S> FromRequest<S, BoxBody> for PrintRequestBody
 where
-    S: Send + Clone,
+    S: Clone + Send + Sync,
 {
     type Rejection = Response;
 

examples/customize-extractor-error/src/main.rs

@@ -58,7 +58,7 @@ struct Json<T>(T);
 #[async_trait]
 impl<S, B, T> FromRequest<S, B> for Json<T>
 where
-    S: Send,
+    S: Send + Sync,
     // these trait bounds are copied from `impl FromRequest for axum::Json`
     T: DeserializeOwned,
     B: axum::body::HttpBody + Send,

examples/customize-path-rejection/src/main.rs

@@ -57,7 +57,7 @@ where
     // these trait bounds are copied from `impl FromRequest for axum::extract::path::Path`
     T: DeserializeOwned + Send,
     B: Send,
-    S: Send,
+    S: Send + Sync,
 {
     type Rejection = (StatusCode, axum::Json<PathError>);
 

examples/jwt/src/main.rs

@@ -124,7 +124,7 @@ impl AuthBody {
 #[async_trait]
 impl<S, B> FromRequest<S, B> for Claims
 where
-    S: Send,
+    S: Send + Sync,
     B: Send,
 {
     type Rejection = AuthError;

examples/validator/src/main.rs

@@ -63,7 +63,7 @@ pub struct ValidatedForm<T>(pub T);
 impl<T, S, B> FromRequest<S, B> for ValidatedForm<T>
 where
     T: DeserializeOwned + Validate,
-    S: Send,
+    S: Send + Sync,
     B: http_body::Body + Send,
     B::Data: Send,
     B::Error: Into<BoxError>,

examples/versioning/src/main.rs

@@ -51,7 +51,7 @@ enum Version {
 impl<S, B> FromRequest<S, B> for Version
 where
     B: Send,
-    S: Send,
+    S: Send + Sync,
 {
     type Rejection = Response;