实现一个类似查找器的树视图，并使用NSOutlineview使用延迟加载来表示它的节点

import Cocoa

class ViewController: NSViewController, NSOutlineViewDataSource, NSOutlineViewDelegate {
    @IBOutlet weak var outlineView: NSOutlineView!
    
    var rootNode: Node = Node(name: "Root", children: [])
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        outlineView.dataSource = self
        outlineView.delegate = self
        
        // 加载根节点数据
        loadChildren(for: rootNode)
    }
    
    // 加载指定节点的子节点数据
    func loadChildren(for node: Node) {
        DispatchQueue.global().async {
            // 模拟异步加载数据
            Thread.sleep(forTimeInterval: 1)
            
            let children = // 加载子节点数据的逻辑，可以是从网络或本地获取数据
            
            DispatchQueue.main.async {
                node.children = children
                outlineView.reloadData()
            }
        }
    }
    
    // MARK: - NSOutlineViewDataSource
    
    func outlineView(_ outlineView: NSOutlineView, numberOfChildrenOfItem item: Any?) -> Int {
        if let node = item as? Node {
            return node.children.count
        }
        return 1 // 根节点数量
    }
    
    func outlineView(_ outlineView: NSOutlineView, child index: Int, ofItem item: Any?) -> Any {
        if let node = item as? Node {
            return node.children[index]
        }
        return rootNode // 根节点
    }
    
    func outlineView(_ outlineView: NSOutlineView, isItemExpandable item: Any) -> Bool {
        if let node = item as? Node {
            return !node.children.isEmpty
        }
        return false
    }
    
    // MARK: - NSOutlineViewDelegate
    
    func outlineView(_ outlineView: NSOutlineView, viewFor tableColumn: NSTableColumn?, item: Any) -> NSView? {
        let view = outlineView.makeView(withIdentifier: NSUserInterfaceItemIdentifier("Cell"), owner: self) as? NSTableCellView
        if let node = item as? Node {
            view?.textField?.stringValue = node.name
        }
        return view
    }
}

class Node {
    let name: String
    var children: [Node]
    
    init(name: String, children: [Node]) {
        self.name = name
        self.children = children
    }
}