How do you use UIEdgeInsets?

I've been trying different ways on the Playground, but the margins are not being implemented. I'm trying to understand the proper way of using UIEdgeInsets (and NSDirectionalEdgeInsets).

My expectation is that the super view should have margins of specified size and the subview should be within that margin, sort of like an invisible border.

Following didn't show any margins for the superview:

Code Block swift
import UIKit
import PlaygroundSupport
let rootView = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
rootView.layoutMargins = UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100)
let subview = UIView()
subview.translatesAutoresizingMaskIntoConstraints = false
NSLayoutConstraint.activate([
  subview.widthAnchor.constraint(equalToConstant: 100),
  subview.heightAnchor.constraint(equalToConstant: 100)
])
subview.backgroundColor = .red
rootView.addSubview(subview)
PlaygroundPage.current.needsIndefiniteExecution = true
PlaygroundPage.current.liveView = rootView

I've also tried with:

Code Block swift
rootView.layoutMargins.top = 100

or instead of Autolayout:

Code Block swift
let subview = UIView(frame: CGRect(origin: .zero, size: .init(width: 100, height: 100)))

No need to mention NSDirectionEdgeInsets didn't work:

Code Block swift
rootView.directionalLayoutMargins = NSDirectionalEdgeInsets(top: 100, leading: 100, bottom: 100, trailing: 100)

I tried it with a view controller, but still futile:

Code Block swift
class MyVC: UIViewController {
  override func viewDidLoad() {
    super.viewDidLoad()
     
    let rootView = UIView(frame: CGRect(x: 0, y: 0, width: 500, height: 500))
    rootView.layoutMargins = UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100)
    self.view.addSubview(rootView)
     
    let subview = UIView()
    subview.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
      subview.widthAnchor.constraint(equalToConstant: 100),
      subview.heightAnchor.constraint(equalToConstant: 100)
    ])
    subview.backgroundColor = .red
    rootView.addSubview(subview)
  }
}

What am I doing wrong?