The main function of this API is to make sure only one plugin is
controlling the device state transitions at a time. The
ReleaseDeviceControl() signal is used to implement a function
WaitForPluginsToReleaseDeviceControl() which is used to block the main
thread if a control plugin is used.
Standard FairRoot is running all the different analysis tasks within one process. FairMQ (Message Queue) allows starting tasks on different processes and provides the communication layer between these processes.