List<ScanResult> dumpBackgroundScanResultQueue() {
        List<ScanResult> retval = mBackgroundScanResultQueue;
        mBackgroundScanResultQueue = new ArrayList<>();
        return retval;
    }
List < ScanResult > dumpBackgroundScanResultQueue ( ) { List < ScanResult > retval = mBackgroundScanResultQueue ; mBackgroundScanResultQueue = new ArrayList < > ( ) ; return retval ; }
@return previoulsy queued scan results delivered in the background