Fix System.NullReferenceException in PSCommSimple.MeasureAsync (PalmSens.Method method, System.Int32 muxChannel, PalmSens.TaskBarrier taskBarrier)

### Version 1.0(1) ###


### Stacktrace ###


### Reason ###


System.NullReferenceException


### Link to App Center ###


* [https://appcenter.ms/users/owenbruce/apps/APM/crashes/errors/3638549851u](https://appcenter.ms/users/owenbruce/apps/APM/crashes/errors/3638549851u)
