如何在自定义CALayer子类的覆盖绘制函数中在macOS上绘制字符串？

import QuartzCore
import CoreText

class CustomLayer: CALayer {
    override func draw(in ctx: CGContext) {
        // 创建NSAttributedString对象
        let string = "Hello, World!"
        let attributes: [NSAttributedString.Key: Any] = [
            .font: NSFont.systemFont(ofSize: 20),
            .foregroundColor: NSColor.black
        ]
        let attributedString = NSAttributedString(string: string, attributes: attributes)
        
        // 创建CTFramesetter对象
        let framesetter = CTFramesetterCreateWithAttributedString(attributedString as CFAttributedString)
        
        // 创建绘制区域
        let path = CGPath(rect: bounds, transform: nil)
        
        // 创建CTFrame对象
        let frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, attributedString.length), path, nil)
        
        // 绘制CTFrame对象
        CTFrameDraw(frame, ctx)
    }
}