Stream ExecNode which will drop the UPDATE_BEFORE messages. This is usually used as an
optimization for the downstream operators that doesn't need the UPDATE_BEFORE messages, but the
upstream operator can't drop it by itself (e.g. the source).
config - per-ExecNode configuration that contains the merged configuration from
various layers which all the nodes implementing this method should use, instead of
retrieving configuration from the planner. For more details check ExecNodeConfig.