step 1, power on!

output.txt

initializing TNC3Connector
initializing CBCentralManager
CBCentralManager started

TNC3-playground.swift

import Foundation
import CoreBluetooth
import PlaygroundSupport

class TNC3Connector: NSObject {
    var centralManager: CBCentralManager!

    override init() {
        super.init()
        print("initializing CBCentralManager")
        centralManager = CBCentralManager(delegate: self, queue: nil)
    }
}

extension TNC3Connector: CBCentralManagerDelegate {
    func centralManagerDidUpdateState(_ central: CBCentralManager) {
        print("CBCentralManager started")
    }
}

// instantiate our class
print("initializing TNC3Connector")
var connector = TNC3Connector()
// run forever
PlaygroundPage.current.needsIndefiniteExecution = true