Improve process_output

process_output is now to finish processing of the output in async nodes,
which means we need to fill the io area before sending the HAVE_OUTPUT
event. This simplifies some things and improves performance because we
don't need to deal with queues and additional checks.

pinos/client/stream.c

@@ -748,9 +748,6 @@ stream_dispatch_func (void             *object,
               break;
           }
         }
-
-        spa_debug_buffer (b);
-
         pinos_signal_emit (&stream->add_buffer, stream, bid->id);
       }