Implement this to initialize your content provider on startup. This method is called for all registered content providers on the application main thread at application launch time. It must not perform lengthy operations, or application startup will be delayed.

You should defer nontrivial initialization (such as opening, upgrading, and scanning databases) until the content provider is used (via Android.Content.ContentProvider.Query(Android.Net.Uri, System.String[], System.String[], System.String[], System.String[]), Android.Content.ContentProvider.Insert(Android.Net.Uri, Android.Content.ContentValues), etc). Deferred initialization keeps application startup fast, avoids unnecessary work if the provider turns out not to be needed, and stops database errors (such as a full disk) from halting application launch.

If you use SQLite, Android.Database.Sqlite.SQLiteOpenHelper is a helpful utility class that makes it easy to manage databases, and will automatically defer opening until first use. If you do use SQLiteOpenHelper, make sure to avoid calling Android.Database.Sqlite.SQLiteOpenHelper.ReadableDatabase or Android.Database.Sqlite.SQLiteOpenHelper.WritableDatabase from this method. (Instead, override Android.Database.Sqlite.SQLiteOpenHelper.OnOpen(Android.Database.Sqlite.SQLiteDatabase) to initialize the database when it is first opened.)

[Android Documentation]