fix thi

src/bun.js/webcore/response.zig

@@ -1785,12 +1785,13 @@ pub const Fetch = struct {
         }
 
         pub fn callback(task: *FetchTasklet, async_http: *http.AsyncHTTP, result: http.HTTPClientResult) void {
-            task.mutex.lock();
-            defer task.mutex.unlock();
             const is_done = !result.has_more;
             // we are done with the http client so we can deref our side
             defer if (is_done) task.deref();
 
+            task.mutex.lock();
+            // we need to unlock before task.deref();
+            defer task.mutex.unlock();
             task.http.?.* = async_http.*;
             task.http.?.response_buffer = async_http.response_buffer;