     // power up
     public func powerOn(afterPowerOn:(()->())?, afterPowerOff:(()->())? = nil) {
         Logger.debug("powerOn")
-        self.afterPowerOnCallback = afterPowerOn
-        self.afterPowerOffCallback = afterPowerOff
-        if self.poweredOn() && self.afterPowerOnCallback != nil {
-            asyncCallback(self.afterPowerOnCallback!)
+        self.afterPowerOn = afterPowerOn
+        self.afterPowerOff = afterPowerOff
+        if self.poweredOn() && self.afterPowerOn != nil {
+            asyncCallback(self.afterPowerOn!)
         }
     }
 

        startScanningForServiceUUIDds(nil, afterPeripheralDiscovered)
    }
    
    public func startScanningForServiceUUIDds(uuids:[CBUUID]!, afterPeripheralDiscoveredCallback:(peripheral:Peripheral, rssi:Int)->()) {
        if !self._isScanning {
            Logger.debug("CentralManager#startScanningForServiceUUIDds")
            self._isScanning = true
            self.afterPeripheralDiscoveredCallback = afterPeripheralDiscoveredCallback
            self.cbCentralManager.scanForPeripheralsWithServices(uuids,options: nil)
        }
    }

            break
        case .PoweredOff:
            Logger.debug("CentralManager#centralManagerDidUpdateState: PoweredOff")
            if let afterPowerOff = self.afterPowerOff {
                self.asyncCallback(afterPowerOff)
            }
            break
        case .PoweredOn:
            Logger.debug("CentralManager#centralManagerDidUpdateState: PoweredOn")
            if let afterPowerOn = self.afterPowerOn {
                self.asyncCallback(afterPowerOn)
            }
            break
        }
