Function close_raft_engine_log_store 

async fn close_raft_engine_log_store(
    log_store: Arc<RaftEngineLogStore>,
) -> Result<()>

Closes the raft-engine WAL, which takes its last reference: raft-engine only closes the active log file when its engine is dropped. If something else still holds the WAL, it is stopped instead and the file stays open until that reference is dropped.