Attempted refreshable UIScrollView

MessagesView.swift

struct Messages: View {
    @EnvironmentObject var account: Account
    @ObservedObject var group: Group
    var body: some View {
        RefreshableScrollView(perform: group.loadOlderMessages) {
            ScrollViewReader { scrollView in
                LazyVStack {
                    ForEach(group.messages, id: \.id) { message in
                        if let user = group.users.first(where: { message.userID == $0.id }) {
                            MessageView(message,
                                        from: user,
                                        own: user.id == account.user.id)
                        }
                    }
                }
            }
        }
        .onAppear {
            group.loadMessages()
        }
    }
}

RefreshableUIScrollView.swift

//
//  RefreshableScrollView.swift
//  Handshake Bets
//
//  Created by Luke Krikorian on 2020-12-29.
//

import SwiftUI

/** https://stackoverflow.com/q/62386390 and https://stackoverflow.com/a/56545872
 and https://stackoverflow.com/a/60168697/7111537 */
struct RefreshableScrollView<Content: View>: UIViewRepresentable {
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }

    private let host: UIHostingController<Content>
    private let action: () -> Void
    private let content: () -> Content
    private var view = UIScrollView()
    private var didRefresh = false

    init(perform action: @escaping () -> Void, @ViewBuilder content: @escaping () -> Content) {
        self.content = content
        self.host = UIHostingController(rootView: self.content())
        self.action = action
    }

    func makeUIView(context: Context) -> UIView {
        host.view.translatesAutoresizingMaskIntoConstraints = false
        host.view.backgroundColor = .clear
        view.addSubview(host.view)
        view.delegate = context.coordinator
        view.refreshControl = UIRefreshControl()
        view.refreshControl?.addTarget(context.coordinator,
                                       action: #selector(Coordinator.handleRefreshControl),
                                       for: .valueChanged)
        let constraints = [
            host.view.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            host.view.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            host.view.topAnchor.constraint(equalTo: view.contentLayoutGuide.topAnchor),
            host.view.bottomAnchor.constraint(equalTo: view.contentLayoutGuide.bottomAnchor),
            host.view.widthAnchor.constraint(equalTo: view.widthAnchor)
        ]
        view.backgroundColor = .red
        view.addConstraints(constraints)
        return view
    }

    func updateUIView(_ uiView: UIView, context: Context) {
        context.coordinator.parent.host.rootView = content()
        if let scrollView = uiView as? UIScrollView {
            let contentRect: CGRect = scrollView.subviews.reduce(into: .zero) { rect, view in
                rect = rect.union(view.frame)
            }
            scrollView.contentSize = contentRect.size
            print("UPDATING!!")
            scrollView.scrollsToBottom(animated: true)
        }
    }

    class Coordinator: NSObject, UIScrollViewDelegate {
        var parent: RefreshableScrollView

        init(_ parent: RefreshableScrollView) {
            self.parent = parent
        }

        @objc func handleRefreshControl(sender: UIRefreshControl) {
            parent.action()
            parent.didRefresh = true
            sender.endRefreshing()
        }
    }
}

extension UIScrollView {
    func scrollsToBottom(animated: Bool) {
        let bottomOffset = CGPoint(x: 0, y: self.contentSize.height - self.bounds.height + self.contentInset.bottom)
        self.setContentOffset(bottomOffset, animated: true)
    }
}