Issue updating @object in Class and reflecting in View

SwiftUIObjectBindingIssue.swift

class ResultsObserver : NSObject, SNResultsObserving { //https://developer.apple.com/documentation/soundanalysis/analyzing_audio_to_classify_sounds
    @ObjectBinding var whistle = Whistle()
    func request(_ request: SNRequest, didProduce result: SNResult) {

        ... //removed for simplicity

        if (classification.identifier == "my classification") {
            print("Detected my classification - setting Object to true")    //This shows in console (when appropriate)
            DispatchQueue.main.async {
                self.whistle.detected = true
            }
        }
    }///end func
}///end class


...// All AVAudioEngine and SoundClassifier functions removed for simplicity


struct ViewDetail: View {
    @ObjectBinding var whistle = Whistle()
  
    var timer: Timer {
        Timer.scheduledTimer(withTimeInterval: 1, repeats: true) {_ in
            DispatchQueue.main.async {
        
                ... //removed for simplicity
        
                print("> checking whistle state, detected=\(self.whistle.detected)")    //I see this in the console, every second, but ALWAYS shows false

            }
        }
    }
    
    ... //removed all SwiftUI Views and Timer logic for simplicity
    
}///end struct

class Whistle: BindableObject {
    var didChange = PassthroughSubject<Void, Never>()
    
    var detected: Bool = false {
        didSet {
            didChange.send(())
        }
    }
}

struct ContentView_Previews : PreviewProvider {
    static var previews: some View {
        ContentView(userData: UserData(users: testData), whistle: Whistle())
    }
}