Move axum-handle-error-extract into axum (#534)

* Move `axum-handle-error-extract` into axum

With 0.4 underway we can now nuke `axum-handle-error-extract` and move
its code directly into axum.

So this replaces the old `HandleErrorLayer` with one that supports async
functions and extractors.

* changelog

* fix CI

examples/key-value-store/src/main.rs

@@ -124,7 +124,7 @@ fn admin_routes() -> Router {
         .layer(RequireAuthorizationLayer::bearer("secret-token"))
 }
 
-fn handle_error(error: BoxError) -> impl IntoResponse {
+async fn handle_error(error: BoxError) -> impl IntoResponse {
     if error.is::<tower::timeout::error::Elapsed>() {
         return (StatusCode::REQUEST_TIMEOUT, Cow::from("request timed out"));
     }

examples/print-request-response/src/main.rs

@@ -29,7 +29,7 @@ async fn main() {
         .route("/", post(|| async move { "Hello from `POST /`" }))
         .layer(
             ServiceBuilder::new()
-                .layer(HandleErrorLayer::new(|error| {
+                .layer(HandleErrorLayer::new(|error| async move {
                     (
                         StatusCode::INTERNAL_SERVER_ERROR,
                         format!("Unhandled internal error: {}", error),

examples/sse/src/main.rs

@@ -26,7 +26,7 @@ async fn main() {
 
     let static_files_service =
         get_service(ServeDir::new("examples/sse/assets").append_index_html_on_directories(true))
-            .handle_error(|error: std::io::Error| {
+            .handle_error(|error: std::io::Error| async move {
                 (
                     StatusCode::INTERNAL_SERVER_ERROR,
                     format!("Unhandled internal error: {}", error),

examples/static-file-server/src/main.rs

@@ -22,7 +22,7 @@ async fn main() {
     let app = Router::new()
         .nest(
             "/static",
-            get_service(ServeDir::new(".")).handle_error(|error: std::io::Error| {
+            get_service(ServeDir::new(".")).handle_error(|error: std::io::Error| async move {
                 (
                     StatusCode::INTERNAL_SERVER_ERROR,
                     format!("Unhandled internal error: {}", error),

examples/todos/src/main.rs

@@ -49,7 +49,7 @@ async fn main() {
         // Add middleware to all routes
         .layer(
             ServiceBuilder::new()
-                .layer(HandleErrorLayer::new(|error: BoxError| {
+                .layer(HandleErrorLayer::new(|error: BoxError| async move {
                     if error.is::<tower::timeout::error::Elapsed>() {
                         Ok(StatusCode::REQUEST_TIMEOUT)
                     } else {

examples/websockets/src/main.rs

@@ -36,7 +36,7 @@ async fn main() {
             get_service(
                 ServeDir::new("examples/websockets/assets").append_index_html_on_directories(true),
             )
-            .handle_error(|error: std::io::Error| {
+            .handle_error(|error: std::io::Error| async move {
                 (
                     StatusCode::INTERNAL_SERVER_ERROR,
                     format!("Unhandled internal error: {}", error),