Stop leaking isahc assumption (#18408)

Users of our http_client crate knew they were interacting with isahc as
they set its extensions on the request. This change adds our own
equivalents for their APIs in preparation for changing the default http
client.

Release Notes:

- N/A

crates/isahc_http_client/src/isahc_http_client.rs

@@ -1,7 +1,6 @@
 use std::{mem, sync::Arc, time::Duration};
 
 use futures::future::BoxFuture;
-use isahc::config::RedirectPolicy;
 use util::maybe;
 
 pub use isahc::config::Configurable;
@@ -36,18 +35,29 @@ impl HttpClient for IsahcHttpClient {
         None
     }
 
-    fn send_with_redirect_policy(
+    fn send(
         &self,
         req: http_client::http::Request<http_client::AsyncBody>,
-        follow_redirects: bool,
     ) -> BoxFuture<'static, Result<http_client::Response<http_client::AsyncBody>, anyhow::Error>>
     {
+        let redirect_policy = req
+            .extensions()
+            .get::<http_client::RedirectPolicy>()
+            .cloned()
+            .unwrap_or_default();
+        let read_timeout = req
+            .extensions()
+            .get::<http_client::ReadTimeout>()
+            .map(|t| t.0);
         let req = maybe!({
             let (mut parts, body) = req.into_parts();
             let mut builder = isahc::Request::builder()
                 .method(parts.method)
                 .uri(parts.uri)
                 .version(parts.version);
+            if let Some(read_timeout) = read_timeout {
+                builder = builder.low_speed_timeout(100, read_timeout);
+            }
 
             let headers = builder.headers_mut()?;
             mem::swap(headers, &mut parts.headers);
@@ -64,10 +74,12 @@ impl HttpClient for IsahcHttpClient {
             };
 
             builder
-                .redirect_policy(if follow_redirects {
-                    RedirectPolicy::Follow
-                } else {
-                    RedirectPolicy::None
+                .redirect_policy(match redirect_policy {
+                    http_client::RedirectPolicy::FollowAll => isahc::config::RedirectPolicy::Follow,
+                    http_client::RedirectPolicy::FollowLimit(limit) => {
+                        isahc::config::RedirectPolicy::Limit(limit)
+                    }
+                    http_client::RedirectPolicy::NoFollow => isahc::config::RedirectPolicy::None,
                 })
                 .body(isahc_body)
                 .ok()