maxPhysicalIds.put(logSrc, physId);
PhysicalLocation physSrc = new PhysicalLocation(logSrc, physId);
// create ack, which has two parts: (1) newly-assigned physical location id; (2) pending asynchronous messages
Tuple ack = new DefaultTuple();
ack.append(physSrc.physId());
DataBag pendingMessages = BagFactory.getInstance().newDefaultBag();
ack.append(pendingMessages);
for (Message rm : rendezvousMessages.get(logSrc)) {
pendingMessages.add(rm.toTuple());