How to attach a file to an email intent?

var email = new Intent (Android.Content.Intent.ActionSend);
email.PutExtra(Android.Content.Intent.ExtraEmail, new string[]{"person1@xamarin.com", "person2@xamrin.com"});

Looking for some

email.PutExtra(Android.Content.Intent.Annex, directoryPath);

Is there something like this or the user need to choose by himself?