add FIXME comment

lib/src/async_db.rs

@@ -100,6 +100,10 @@ where
 
         self.table.push(pos);
 
+        // FIXME
+        // this will break WriterSink::poll_ready (will wait forever), but not Writer::load
+        // tokio::time::sleep(std::time::Duration::from_secs(1)).await;
+
         Ok(())
     }