HeadlessChrome chrome = new HeadlessChrome(
    HeadlessChrome.DefaultAppPathMac
);
using (chrome) {
    chrome.Start();
    chrome.Page.Navigate("http://google.com/");
    var png = chrome.Page.CaptureScreenshot();
    File.WriteAllBytes("CaptureScreenshot.png", png.Data);
    chrome.Delay(500);
}

HeadlessChrome chrome = new HeadlessChrome(
    HeadlessChrome.DefaultAppPathMac
);
using (chrome) {
    chrome.Page.FrameNavigated += (sender, e) => {
        Console.WriteLine(e);
    };
    chrome.Start();
    chrome.Page.Enable();
    chrome.Page.Navigate("http://google.com/");
    chrome.Delay(500);
}