PdfOptions example (#1345)

Author: kblok

docfx_project/api/index.md

@@ -42,6 +42,31 @@ await page.GoToAsync("http://www.google.com");
 await page.PdfAsync(outputFile);
 ```
 
+### Generate PDF files with custom options
+
+```cs
+await new BrowserFetcher().DownloadAsync(BrowserFetcher.DefaultRevision);
+var browser = await Puppeteer.LaunchAsync(new LaunchOptions
+{
+    Headless = true
+});
+var page = await browser.NewPageAsync();
+await page.GoToAsync("http://www.google.com");
+await page.PdfAsync(outputFile, new PdfOptions
+{
+    Format = PaperFormat.A4,
+    DisplayHeaderFooter = true,
+    MarginOptions = new MarginOptions
+    {
+        Top = "20px",
+        Right = "20px",
+        Bottom = "40px",
+        Left = "20px"
+    },
+    FooterTemplate = "<div id=\"footer-template\" style=\"font-size:10px !important; color:#808080; padding-left:10px\">Footer Text</div>"
+});
+```
+
 ## Inject HTML
 
 ```cs

docfx_project/index.md

@@ -21,6 +21,6 @@ Puppeteer Sharp is a .NET port of the official [Node.JS Puppeteer API](https://g
 
 # Useful links
 
-* Slack channel [#puppeteer-sharp](https://join.slack.com/t/puppeteer/shared_invite/enQtMzU4MjIyMDA5NTM4LTM1OTdkNDhlM2Y4ZGUzZDdjYjM5ZWZlZGFiZjc4MTkyYTVlYzIzYjU5NDIyNzgyMmFiNDFjN2UzNWU0N2ZhZDc)
+* Slack channel [#puppeteer-sharp](https://puppeteer.slack.com/join/shared_invite/enQtMzU4MjIyMDA5NTM4LWI0YTE0MjM0NWQzYmE2MTRmNjM1ZTBkN2MxNmJmNTIwNTJjMmFhOWFjMGExMDViYjk2YjU2ZmYzMmE1NmExYzc)
 * [StackOverflow](https://stackoverflow.com/search?q=puppeteer-sharp)
 * [Issues](https://github.com/kblok/puppeteer-sharp/issues?utf8=%E2%9C%93&q=is%3Aissue)