Function groups_leaving_node_affects 

pub fn groups_leaving_node_affects(
    node: NodeId,
    all_groups: &[RaftGroupId],
    live_nodes_before: &[NodeId],
    live_nodes_after: &[NodeId],
    replication_factor: u32,
) -> Vec<RaftGroupId>

Groups whose desired voter set loses node when it departs the live set (cluster leave).