systemFlow

Listen for system events on this channel.

Opt in to the replication-ready notification with BroadcastJoinConfig.replicationReady: true when creating the channel, then watch for RealtimeSystemPayload.status == "ok" to know the Postgres replication connection is ready.

Errors arrive with RealtimeSystemPayload.status == "error", e.g. when the server refuses a postgres_changes subscription.