let fakeObject = FakeClass()
fakeObject.start()
fakeObject.exitAndCancelOperations()

let operationBlock1 = BlockOperation()
operationBlock1.addExecutionBlock { [unowned operationBlock1] in
  guard !operationBlock1.isCancelled else {
    print("Operation 1: Cancelled")
    return
  }
  
  self.checkFacebook()
}

let operationBlock2 = BlockOperation()
operationBlock2.addExecutionBlock { [unowned operationBlock2] in
  guard !operationBlock2.isCancelled else {
    print("Operation 2 (exercise): Cancelled before startExecise even starts")
    return
  }
	
  self.startExecise()
	
  guard !operationBlock2.isCancelled else {
    print("Operation 2 (exercise): Cancelled before it finishes")
    return
	}
  
  self.endExecise() //Will not reach this point because it has already been cancelled
}

let operationBlock3 = BlockOperation()
operationBlock3.addExecutionBlock { [unowned operationBlock3] in
	
  self.getCoffee() //Will not reach this point because it has already been cancelled
  
  guard !operationBlock3.isCancelled else {
	  print("Operation 3: Cancelled")
    return
  }

  self.drinkCoffee()
}

operationQueue.addOperation(operationBlock1) //checkFacebook
operationQueue.addOperation(operationBlock2) //exercise
operationQueue.addOperation(operationBlock3) //coffee

func exitAndCancelOperations(in operationQueue: OperationQueue) {
  print("Cancelling all operations.")
  operationQueue.cancelAllOperations()
}

Operation 1 (checkFacebook): Started
Operation 1 (checkFacebook): Completed.
Operation 2 (exercise): Started
Cancelling all operations.
Operation 2 (exercise): Cancelled before it finishes
Done!

Operation 1 (checkFacebook): Started
Operation 1 (checkFacebook): Completed.
Operation 2 (exercise): Started
Operation 2 (exercise): Completed
Operation 3 (coffee): Started
Operation 3 (coffee): Completed.
Done!