合并-两次订阅PassthroughSubject的发布者

Question

我尝试订阅两次通过PassthroughSubject创建的发布者，并且在PassthroughSubject触发值时仅执行其中一个。

这是我尝试过的：

class Worker {
   let stringGeneratorResultSubject: PassthroughSubject<String, Error>
  
   init(stringGeneratorResultSubject: PassthroughSubject<String, Error>) {
        self.stringGeneratorResultSubject = stringGeneratorResultSubject
   }

   func generateString() {
       stringGeneratorResultSubject.send("someValue")
   }
}

class A {
    let workerObj: Worker
    let workerObjPublisher: AnyPublisher<String, Swift.Error>
    init(workerObj: Worker, 
         workerObjPublisher: AnyPublisher<String, Swift.Error>) {
       self.workerObj = workerObj
       self.workerObjPublisher = workerObjPublisher
       super.init()
     
       getString()
    }

   func getString() {
      workerObjPublisher.sink { result in 
        // do something with result for
     }.store(in: &cancellable)

     workerObj.generateString()
  }
}

class B {
    let workerObjPublisher: AnyPublisher<String, Swift.Error>
    init(workerObjPublisher: AnyPublisher<String, Swift.Error>) {
       self.workerObjPublisher = workerObjPublisher
       super.init()
     
       loadString()
    }

   func loadString() {
      workerObjPublisher.sink { result in 
        // do something with result
     }.store(in: &cancellable)
   }

 }

class Parent {
   lazy var stringGeneratorResultSubject: PassthroughSubject<String, Swift.Error> = .init()
   lazy var workerObj: Worker = .init(stringGeneratorResultSubject: stringGeneratorResultSubject)
   lazy var aObj: A = .init(workerObj: workerObj, 
                            workerObjPublisher: stringGeneratorResultSubject.eraseToAnyPublisher())

   lazy var bObj: B = .init(workerObjPublisher: stringGeneratorResultSubject.eraseToAnyPublisher())
   
   _ = bObj

   aObj.getString()
}

仅调用class A中getString()的订阅块。 class B中loadString()的订阅块未执行。我想念什么吗？