How to set AUAudioUnit format

How do I set AUAuidioUnit input/output bus format without AVAudioEngine?

import AVFoundation
import CoreAudioKit
class VicewController: UIViewController {
    lazy var CD = { AVAudioUnitComponentManager.shared().components(passingTest:{$0.0.name == "AUDelay"}).first!.audioComponentDescription }()
    var unit:AVAudioUnit?
    override func viewDidLoad() {
        super.viewDidLoad()
        AVAudioUnit.instantiate(with: self.CD, options: [.loadOutOfProcess]) { (unit, error) in
            //Set format on input and output bus format?
            try! unit!.auAudioUnit.allocateRenderResources()
        }
    }
}

I thougth it would be `inputBusses.replaceBusses` but it doesnt seem to work.