share image Xamarin Ios -

i'm using xamarin forms, , in application has button share problem being in android application got doing intent in application ios'm not knowing how do, me?

using android

public async task<bool> share(imagesource image)     {         intent shareintent = new intent(intent.actionsend);          bitmaptoshare = await getbitmap (image);          if (bitmaptoshare != null) {              createdirectoryforpictures("xpto");              var filepath = system.io.path.combine (dir.absolutepath, string.format("xpto_{0}.png",guid.newguid()));             var stream = new filestream (filepath, filemode.create);             bitmaptoshare.compress (bitmap.compressformat.png, 100, stream);             stream.close ();              java.io.file file = new java.io.file (filepath);              shareintent.settype ("image/*");             shareintent.putextra (intent.extrastream, android.net.uri.fromfile (file));             shareintent.addflags (activityflags.grantreaduripermission);             forms.context.startactivity (intent.createchooser (shareintent, "compartilhar"));         }          return true;     } 

    private static async task shareimageasyc(imagesource image, string message, string url = null)     {         var handler = image.gethandler();          if (handler == null) return;          var uiimage = await handler.loadimageasync(image);          var items = new list<nsobject> { new nsstring(message ?? string.empty) };         if (!url.isnullorempty())             items.add(new nsstring(url));         items.add(uiimage);          var controller = new uiactivityviewcontroller(items.toarray(), null);          uiapplication.sharedapplication.keywindow.rootviewcontroller.gettopviewcontroller()             .presentviewcontroller(controller, true, null);     } 

from: https://github.com/jimbobbennett/jimlib.xamarin/blob/master/jimlib.xamarin.ios/sharing/share.cs