Race Condition in ASCOM Driver

[ghilios]

Hi, I'm a NINA contributor. I was investigating a user's issue with the AF3 device and I root caused it to a race condition in your code.

Please look at https://github.com/DeepSkyDad/AF3/blob/master/DeepSkyDad.AF3.ASCOM/DriverExtension.cs. "hasHandle" is a class-scope variable. If the device is in the middle of responding to one command and takes more than 2 seconds when another call comes in, the 2nd one will fail and set "hasHandle" to false. Then when the first completes it'll never release the mutex and all calls from then on will fail. I built a fix for the user by moving the variable just to the function.

[DeepSkyDad]

Hi, thank you for issue report, nice catch! Fixed in fdbe1f7