diff --git a/include/actsim_agent/downloader.hpp b/include/actsim_agent/downloader.hpp
index 24fcb61..b2c2084 100644
--- a/include/actsim_agent/downloader.hpp
+++ b/include/actsim_agent/downloader.hpp
@@ -31,6 +31,8 @@
 #include <cluster/db_client.hpp>
 #include "task_interface.hpp"
 
+#define NOTHING_AVAILABLE_SLEEP_TIME 500ms
+
 class Downloader {
 
     public:
@@ -45,7 +47,7 @@ class Downloader {
     void thread_run();
     bool fetch_tasks(size_t n);
     bool fetch_design(const db::uuid_t& id, std::string& design);
-    void reopen_task(const db::uuid_t& id);
+    void reopen_task(const db::uuid_t& id, bool halt);
 
     std::unique_ptr<std::thread> downloader_thread;
     std::unique_ptr<db::Connection> conn;