The sleep used to simulate data load times is ignoring InterruptedExceptions.
(This is intended and in line with SystemClock.sleep()). However, when a
Loader cancels an ongoing load, it uses interrupts. To be able to catch these
and to immediately return from the reading data source, a handler callback
is used instead of the sleep() method which allows interuptable waiting.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168212652
