Close intermediate 429 responses before retry to prevent resource leaks

When a request receives a 429 rate limit response and the client
retries, the previous Response (and its underlying connection) was
not being closed. This could leak connections from the OkHttp
connection pool under sustained rate limiting. Close the response
body before sleeping and retrying.

Author: jeffreyparker

duo-client/src/main/java/com/duosecurity/client/Http.java

@@ -318,6 +318,10 @@ private Response executeRequest(Request request) throws Exception {
         return response;
       }
 
+      // Close the 429 response to release the connection back to the pool before retrying
+      if (response.body() != null) {
+        response.close();
+      }
       sleep(backoffMs + nextRandomInt(1000));
       backoffMs *= BACKOFF_FACTOR;
     }