+why did persist conversion fail with segv
+ moving features in non-saved memory
+
+why can I not repro persist conversion failure
+
+multiplex should have restart loop limiting
+why did removing +persist.* not fix it
+running --persist-convert-entrails on bad thing error handling broken
+version number should be reported / preserved somehow
+should expire dumps, eventually
+want realtime kernel for bessar
+
+
bugs
at converging points eg X8, can we make train
go from (say) X6 fast enough that when we stop