Devices incorrectly reported as not connected

[MarkRivers]

asynReport can incorrectly show a device is not connected when it really is.

This typically happens when the driver has multiDevice=true and some device addresses only communicate via driver callbacks, e.g. records with SCAN=I/O Intr. This is discussed in this tech-talk thread. https://epics.anl.gov/tech-talk/2022/msg00236.php

The solution would appear to be to have asynManager change the flag to indicate a device is connected if it receives a driver callback for that port and address. I have not investigated to see how easy this would be.