separate files flushing code

Author: kalessin

shub_workflow/issuer/__init__.py

@@ -195,6 +195,9 @@ def send_file(self, output_slot: Union[Slot, None], source: Source):
     def on_close(self):
         super().on_close()
         self.seen.close()
+        self.flush_files()
+
+    def flush_files(self):
         for slot, sources in self.items_queue.items():
             for source in list(sources.keys()):
                 if len(sources[source]) > 0: