SaschaDittmann/Xamarin.NotificationHub — pull request #7 by nitescua (2014-12-09 16:16:05+00:00)
Title: set ETag to overwrite when updating or deleting a registration

The ETag needs to be set to "*" when updating or deleting a
registration, otherwise it returns
"Error 412 Precondition Failed–ETag header missing or invalid"

This is according to the code in Microsoft.WindowsAzure.Messaging.dll,
which is the Notification Hub client for Windows Phone