foo.cs

		public override NSData GetAsData (string typeName, out NSError outError)
		{
			// Insert code here to write your document to data of the specified type. 
			// If outError != NULL, ensure that you create and set an appropriate error when returning nil.
			outError = new NSError ();
			return NSData.FromString ("asdf");
		}

		public override bool ReadFromData (NSData data, string typeName, out NSError outError)
		{
			// Insert code here to read your document from the given data of the specified type. 
			// If outError != NULL, ensure that you create and set an appropriate error when returning NO.
			outError = new NSError ();
			return true;
		}