tryToUnderstadnViewLifecycle.swift

import UIKit

class ViewController: UIViewController {

    @IBAction func unwind(segue: UIStoryboardSegue){
        if segue.identifier == "goToSeconViewController" {
            segue.source as! SecondViewController
        }
    }

    override func viewDidLoad() {
        super.viewDidLoad()
        print("firstViewDidLoad")
    }
    override func viewWillAppear(_ animated: Bool) {
        print("firstViewWillAppear")
    }
    override func viewDidAppear(_ animated: Bool) {
        print("firstViewDidAppear")
    }
    override func viewWillDisappear(_ animated: Bool) {
        print("firstviewWillDisappear")
    }
    override func viewDidDisappear(_ animated: Bool) {
        print("firstviewDidDisappear")
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    
}