I believe joins work without simultaneous pushing. One side can build first, the other side can probe in a pushed fashion after but not necessarily simultaneous

I believe joins work without simultaneous pushing. One side can build first, the other side can probe in a pushed fashion after but not necessarily simultaneously. “Trigger” is not necessarily the relationship, between build and probe sides though it could be. The DAG paths that produce/push the probe can be triggered by the completion of the build. “Happens after” is more strictly apt.