Allow meta_only streams

src/AsapoWorker/streamer.py

@@ -20,12 +20,13 @@ def has_newer_substream(substream, substream_list):
 class Streamer:
     def __init__(
             self, receiver, worker, delay_on_error=3,
-            end_of_stream_callback=None):
+            end_of_stream_callback=None, meta_only=False):
         self.receiver = receiver
         self.worker = worker
         self.initial_delay_on_error = delay_on_error
         self.delay_on_error = delay_on_error
         self.end_of_stream_callback = end_of_stream_callback
+        self.meta_only = meta_only
         self.likely_done = False
         self.stopped = Event()
 
@@ -48,7 +49,7 @@ class Streamer:
 
     def _get_next(self):
         try:
-            data, metadata = self.receiver.get_next(meta_only=False)
+            data, metadata = self.receiver.get_next(meta_only=self.meta_only)
         except EndOfStreamError as err:
             log.info(format_error(err))
             self._handle_receiver_temporary_error()