Called on a worker thread to perform the actual load and to return the result of the load operation. Implementations should not deliver the result directly, but should return them from this method, which will eventually end up calling Loader.deliverResult(D) on the UI thread. If implementations need to process the results on the UI thread they may override Loader.deliverResult(D) and do so there. To support cancellation, this method should periodically check the value of AsyncTaskLoader.IsLoadInBackgroundCanceled and terminate when it returns true. Subclasses may also override AsyncTaskLoader.CancelLoadInBackground to interrupt the load directly instead of polling AsyncTaskLoader.IsLoadInBackgroundCanceled. When the load is canceled, this method may either return normally or throw Android.OS.OperationCanceledException. In either case, the Android.Content.Loader will call AsyncTaskLoader.onCanceled(D) to perform post-cancellation cleanup and to dispose of the result object, if any.

[Android Documentation]