First segue with 2 second delay - swift

Question

I have a button (searchButton) in the parent view controller. The action for the button (searchButtonTapped) is to segue to Result View Controller as shown below.
#IBAction func searchButtonTapped(_ sender: Any) {
let mainStoryboard = UIStoryboard(name: "SearchResult", bundle: Bundle.main)
guard let resultViewController = mainStoryboard.instantiateViewController(withIdentifier: "ResultViewController") as? ResultViewController else { return }
resultViewController.resultText = initialText
navigationController?.pushViewController(resultViewController, animated: true)
}
When I tapped the button (searchButton) for the first time, the segue action happens but with 2 second delay. When I return to the parent view controller and tap the button again, from the second time, the segue is smooth. There is a two second delay only for the very first segue after the app is launched. What am I doing wrong to have the delay here? Your thoughts would be greatly appreciated. Thanks.
Here is the viewDidLoad for the child view controller (ResultViewController). I tried to print "A" to "F" in order to identify the step that causes delay, but as soon as I tap searchButton, All from A to F prints without delay. And then after printing "F", it delays about 2 seconds before the screen gets updated with the push segue.
override func viewDidLoad() {
super.viewDidLoad()
print("A")
populateDataArray(resultText.isEmpty)
resetSelectedItemArray(movingIn: true)
print("B")
headerView = listTableView.tableHeaderView as? ResultTableHeaderView
headerView.bannerImageView.contentMode = .scaleAspectFill
listTableView.tableHeaderView = nil
listTableView.addSubview(headerView)
listTableView.contentInset = UIEdgeInsets(top: tableHeaderViewHeight, left: 0, bottom: 0, right: 0)
print("C")
initializeHeaderView()
setupRightBarButtonItems()
setupInformationBar()
setupTableViewStyle()
print("D")
navigationItem.setHidesBackButton(true, animated: false)
let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()
layout.minimumInteritemSpacing = 5
layout.scrollDirection = .horizontal
resultCollectionView.collectionViewLayout = layout
print("E")
resultCollectionView.delegate = self
resultCollectionView.dataSource = self
listTableView.delegate = self
listTableView.dataSource = self
stickyDropDownTableView.delegate = self
stickyDropDownTableView.dataSource = self
informationDropDownTableView.delegate = self
informationDropDownTableView.dataSource = self
print("F")
}

Answer 1

Usually this happens when the destination view is particularly complex and certainly require any heavy processing to load, and it takes that bit of time. But your's doesn't look like. So, You can perform your segue inside on main thread and that will ease up the problem.
DispatchQueue.main.async {
navigationController?.pushViewController(resultViewController, animated: true)
}