DataLogger art processes "exited with code 131"
While not a very destructive error, it does create an error message. Ron and I determined that the cause was an insufficient default delay between SMEM::endOfData broadcasting the EndOfData Fragment and ShutdownArtProcesses being called.
Adjusting the default "expected_art_event_processing_time_us" parameter to 1s caused the error message to go away on ironwork.
The issue is simply that art has to close the data file before it can exit, which was taking ~0.3s, while SMEM was only giving it 0.1s. However, art handles the subsequent SIGQUIT correctly, and the only effect is the generation of the error message. With this change, the demo can run without any error messages at all.