write without response assumes we can process the write immediately

[markohara]

Summary: If we enqueue a large number of .withoutResponse writes, eventually we reach a point where the Core Bluetooth write buffer can no longer take any more writes, resulting in a crash. Apple has added the peripheralIsReady delegate method to allow you to ensure another write can happen successfully when writing without response.

in WriteCharacteristic instead of automatically processing requests of this type, we should use peripheralIsReady to inform us that we are able to process this write.