Function remote_scan_client 

pub async fn remote_scan_client(
    pool: &QueryClientPool,
    kv: &Arc<dyn ClusterKv>,
    peer: NodeId,
    table_name: &str,
    projection: Option<Vec<usize>>,
    filter_sql: Option<String>,
) -> Result<Option<RemoteBatchStream>, String>

Scan table_name on peer as a lazy Arrow-IPC stream. Ok(None) means the peer is unreachable (no published address) and should be skipped, not failed.

Errors

Transport/timeout while establishing; post-stream failures surface as Err items.