Remove unneeded bounds on S in FromRequest(Parts) implementations

This doesn't actually allow using non-Send or non-Sync state types, but
it makes the docs simpler.

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

@@ -81,16 +81,11 @@ struct BufferRequestBody(Bytes);
 
 // we must implement `FromRequest` (and not `FromRequestParts`) to consume the body
 #[async_trait]
-impl<S> FromRequest<S, BoxBody> for BufferRequestBody
-where
-    S: Send + Sync,
-{
+impl<S> FromRequest<S, BoxBody> for BufferRequestBody {
     type Rejection = Response;
 
-    async fn from_request(req: Request<BoxBody>, state: &S) -> Result<Self, Self::Rejection> {
-        let body = Bytes::from_request(req, state)
-            .await
-            .map_err(|err| err.into_response())?;
+    async fn from_request(req: Request<BoxBody>, _: &S) -> Result<Self, Self::Rejection> {
+        let body: Bytes = req.extract().await.map_err(|err| err.into_response())?;
 
         do_thing_with_request_body(body.clone());
 

examples/jwt/src/main.rs

@@ -122,13 +122,10 @@ impl AuthBody {
 }
 
 #[async_trait]
-impl<S> FromRequestParts<S> for Claims
-where
-    S: Send + Sync,
-{
+impl<S> FromRequestParts<S> for Claims {
     type Rejection = AuthError;
 
-    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
+    async fn from_request_parts(parts: &mut Parts, _: &S) -> Result<Self, Self::Rejection> {
         // Extract the token from the authorization header
         let TypedHeader(Authorization(bearer)) = parts
             .extract::<TypedHeader<Authorization<Bearer>>>()

examples/parse-body-based-on-content-type/src/main.rs

@@ -60,7 +60,6 @@ enum JsonOrForm<T, K = T> {
 impl<S, B, T, U> FromRequest<S, B> for JsonOrForm<T, U>
 where
     B: Send + 'static,
-    S: Send + Sync,
     Json<T>: FromRequest<(), B>,
     Form<U>: FromRequest<(), B>,
     T: 'static,
@@ -68,7 +67,7 @@ where
 {
     type Rejection = Response;
 
-    async fn from_request(req: Request<B>, _state: &S) -> Result<Self, Self::Rejection> {
+    async fn from_request(req: Request<B>, _: &S) -> Result<Self, Self::Rejection> {
         let content_type_header = req.headers().get(CONTENT_TYPE);
         let content_type = content_type_header.and_then(|value| value.to_str().ok());
 

examples/validator/src/main.rs

@@ -70,7 +70,7 @@ where
     type Rejection = ServerError;
 
     async fn from_request(req: Request<B>, state: &S) -> Result<Self, Self::Rejection> {
-        let Form(value) = Form::<T>::from_request(req, state).await?;
+        let Form(value): Form<T> = req.extract().await?;
         value.validate()?;
         Ok(ValidatedForm(value))
     }

examples/versioning/src/main.rs

@@ -48,13 +48,10 @@ enum Version {
 }
 
 #[async_trait]
-impl<S> FromRequestParts<S> for Version
-where
-    S: Send + Sync,
-{
+impl<S> FromRequestParts<S> for Version {
     type Rejection = Response;
 
-    async fn from_request_parts(parts: &mut Parts, _state: &S) -> Result<Self, Self::Rejection> {
+    async fn from_request_parts(parts: &mut Parts, _: &S) -> Result<Self, Self::Rejection> {
         let params: Path<HashMap<String, String>> =
             parts.extract().await.map_err(IntoResponse::into_response)?;