public static <TResult> Task<TResult> callInBackground(Callable<TResult> callable) {
    return call(callable, BACKGROUND_EXECUTOR, null);
  }
public static < TResult > Task < TResult > callInBackground ( Callable < TResult > callable ) { return call ( callable , BACKGROUND_EXECUTOR , null ) ; }
Invokes the callable on a background thread, returning a Task to represent the operation.

If you want to cancel the resulting Task throw a {@link java.util.concurrent.CancellationException}
from the callable.