How to read a local value correctly both in Combine's sink scope and in the scope that Combine's sink was defined?

Now I want to notify value change from delegate event to another func() and returns the new value with callback(). To do that, I tried to write test program as below. However, problem happened.

import SwiftUI

struct ContentView: View {
   
  let cst = CombineSinkTest()
   
  var body: some View {
    Button(action: {
      cst.sinkTest(stCount: 0){ sinkResult in
        print("finish")
      }
    }){
      Text("Push")
    }

  }
}

import Foundation
import Combine

final public class CombineSinkTest: NSObject{
   
  var stringPublisher = PassthroughSubject<String?, Never>()
  var cancellables = [AnyCancellable]()
     
  private var globalNum = 0
  var sinkDefinedFlag = false
   
  func sinkTest(stCount: Int, completion: @escaping (Bool) -> Void){
    var localCount = stCount
     
    childSink(count: localCount){ childResult in
      localCount += 1
      DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
        self.sinkTest(stCount: localCount){ stResult in
          completion(true)
        }
      }
    }
  }
   
  func childSink(count: Int, completion: @escaping (Bool) -> Void ){
    globalNum += 1
    let localNum = globalNum
     
    print("globalNum: \(localNum)")
     
    if(sinkDefinedFlag == false) {
      self.stringPublisher
        .sink(receiveCompletion: { print ("completion: \($0)") },
         receiveValue: {
          print ("received: \($0)")
          print("local value: \(localNum)")
          completion(true)
         })
        .store(in: &cancellables)
      sinkDefinedFlag = true
    }

(a)    generateNotification()
     
  }
   
(a)  private func generateNotification() {
    stringPublisher.send("")
  }

}

(a) is test-purpose. (a)'s func is planned to be delegate event.

I want to let receiveValue: in .sink to use localCount number. However, localCount won't increase at all...

globalNum: 1
localNum in caller of .sink: 1
received: Optional("")
localNum in .sink: 1 

globalNum: 2
localNum in caller of .sink: 2
received: Optional("")
localNum in .sink: 1 

globalNum: 3
localNum in caller of .sink: 3
received: Optional("")
localNum in .sink: 1 

globalNumber is increasing. And, localNum in func defining .sink. However, localCount in .sink closure won't increase. How should I change the code for passing updated localNum into .sink closure?

Sorry for not good English... Best regards,