Apply deadline across redirects. (#313)

Previously, each redirect could take timeout time, so a series of slow
redirects could run for longer than expected, or indefinitely.

src/unit.rs

@@ -38,6 +38,7 @@ impl Unit {
         url: &Url,
         headers: &Vec<Header>,
         body: &SizedReader,
+        deadline: Option<time::Instant>,
     ) -> Self {
         //
 
@@ -99,14 +100,6 @@ impl Unit {
             .cloned()
             .collect();
 
-        let deadline = match agent.config.timeout {
-            None => None,
-            Some(timeout) => {
-                let now = time::Instant::now();
-                Some(now.checked_add(timeout).unwrap())
-            }
-        };
-
         Unit {
             agent: agent.clone(),
             method: method.to_string(),
@@ -213,7 +206,14 @@ pub(crate) fn connect(
         history.push(unit.url.to_string());
         body = Payload::Empty.into_read();
         // recreate the unit to get a new hostname and cookies for the new host.
-        unit = Unit::new(&unit.agent, &new_method, &new_url, &unit.headers, &body);
+        unit = Unit::new(
+            &unit.agent,
+            &new_method,
+            &new_url,
+            &unit.headers,
+            &body,
+            unit.deadline,
+        );
     };
     resp.history = history;
     Ok(resp)