Determinate class to be used as background freeze detection thread.
Class to create by InitCheckFreeze function.
This variable is used by InitCheckFreeze function to create a new background freeze detection thread. You can use build-in classes ( TMainThreadFreezeDetectionThread or TWCTFreezeDetectionThread) or implement your own freeze detection thread class. Class has to be descendant of TFreezeThread and it must override Execute method.