satman: support sub-subkernels, routing

- support async flag
- source in packets
- rerouting packets

src/runtime/src/rtio_mgt.rs

@@ -96,6 +96,9 @@ pub mod drtio {
                             drtioaux_async::send(linkno, &Packet::SubkernelMessageAck { destination: source })
                                 .await
                                 .unwrap();
+                            let mut countdown = timer.countdown();
+                            // give the satellites some time to process
+                            delay(&mut countdown, Milliseconds(10)).await;
                         }
                         // routable packets
                         Packet::DmaAddTraceRequest { destination, .. }