step4.swift

func findConnectedPrinter(completion: (Bool) -> Void) {
    let connectedDevices = manager.connectedAccessories
    for device in connectedDevices {
        if device.protocolStrings.contains(“com.zebra.rawport”) {
            serialNumber = device.serialNumber
            connectToPrinter(completion: { completed in
                completion(completed)
            })
        }
    }
}
private func connectToPrinter( completion: (Bool) -> Void) {
    printerConnection = MfiBtPrinterConnection(serialNumber: serialNumber)
    printerConnection?.open()
    completion(true)
}