Status: IN
`sync()` drains all pending queues from every node before distributing any changes, preventing intra-round cascading where one node's change would trigger further propagation within the same sync round
Source: entries/2026/05/29/multi-leader-replication-multi_leader.md
pending_by_node = {}
for nid in self._node_order:
pending_by_node[nid] = self._nodes[nid].get_pending_changes()
# then distribute to peers