Unrelated question to the above: is there a reason SyncInMemoryLauncher uses a weakref of the instance passed in from initialze instead of the instance passed to launch_run? https://github.com/dagster-io/dagster/blob/1aa474e04ccd91b089cffe4a597799dab4de5c3a/python_modules/dagster/dagster/core/launcher/sync_in_memory_run_launcher.py#L46