I'm developing an App, a function is through the bluetooth firmware upgrade. there is a problem now. when I send data via bluetooth, App into the background, the data sent to immediately stop, peripheralIsReadyToSendWriteWithoutResponse will not be invoked, At the same time canSendWriteWithoutResponse always returns false. When I open the App again, peripheralIsReadyToSendWriteWithoutResponse still will not be invoked, canSendWriteWithoutResponse or returns false. I have set Acts as a Bluetooth LE accessory and Uses Bluetooth LE accessories. Is there a good way to send data to the device when my App goes into the background?