Yeah, this is not great... I created this place holder just to fill in the blank between switching the tab and finish reading the file. For images, it actually takes some time.

In the future, we should have some more elegant way of doing this as mentioned in the TODO on [Line 39](https://github.com/dart-lang/spark/pull/239/files#diff-310e6d6d60491f6676677450aefe385fR39).