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ScreenshotDataAsync method never returns if a Page object is being created on a separate thread.

See original GitHub issue

Description

ScreenshotDataAsync method never returns if the code creates a new browser page during that operation.

The purpose for this is to create an auto-refillable ConcurrentQueue of pages that would provide the next available page to a client that asks for it. The idea is to create 20 pages via NewPageAsync and hand them out to clients who ask for a page. When the amount of available pages gets down to 3, create more pages.

Complete minimal example reproducing the issue

The code starts the browser, creates a page, goes to a new thread to create the screenshot. Meanwhile, the main thread creates 20 more new pages.

void Main(string[] args) {
    var options = new LaunchOptions() {
        // replace with your own or downllad
        ExecutablePath = @"C:\Projects\net2\Tools\WidgetImages\chromium\chrome.exe",
        Headless = false
    };
    Browser browser = Puppeteer.LaunchAsync(options).Result;
    Page page = browser.NewPageAsync().Result;

    Task.Run(() => TakeScreenshot(page, "https://www.google.com"));

    // create a bunch of pages
    var pagesQueue = new ConcurrentQueue<Page>();
    for (int i = 0; i < 20; i++) {
        Debug.WriteLine(DateTime.Now.Ticks + $" CreatePage {i}");
        pagesQueue.Enqueue(browser.NewPageAsync().Result);
    }

    Console.ReadKey();
}

public static void TakeScreenshot(Page page, string url) {
    var viewportOptions = new ViewPortOptions {
        Width = 800,
        Height = 800
    };
    page.SetViewportAsync(viewportOptions).Wait();
    var webPage = page.GoToAsync(url).Result;

    // get the screenshot
    Debug.WriteLine("ScreenshotDataAsync start");
    var imageBytes = page.ScreenshotDataAsync().Result;
    Debug.WriteLine("ScreenshotDataAsync End");
    
    var ms = new MemoryStream(imageBytes);
    Image img = Image.FromStream(ms);

    string desktopDir = Environment.GetFolderPath(SpecialFolder.DesktopDirectory);
    string path = Path.Combine(desktopDir, "img1.png");
    img.Save(path);
}