[In Progress] Move Cache module to kotlin about store

[ychescale9]

Thanks!

[ychescale9]

@digitalbuddha I can have a go at this. Could you elaborate on the second requirement? Would this involve changing current APIs?

[digitalbuddha]

No changes from current api. Here is the current builder, we would need the same in the new impl: https://github.com/dropbox/Store/blob/1810355341a9d6f2f8dc17e117d3dec31b10407b/store/src/main/java/com/dropbox/android/external/store4/impl/RealStore.kt#L58

Here is the current interface for usage:
https://github.com/dropbox/Store/blob/1810355341a9d6f2f8dc17e117d3dec31b10407b/cache/src/main/java/com/dropbox/android/external/cache3/Cache.java#L12

We do not need to support the blocking get call which calls a loader. That was an api that store3 had that is no longer needed.

@Nonnull
  V get(K key, Callable<? extends V> valueLoader) throws ExecutionException;

Appreciate the help but as a warning we would expect 100% test coverage before accepting the contribution. Current implementation does not have many tests in repo due it being taken from Guava which had extensive testing

[ychescale9]

We do not need to support the blocking get call which calls a loader. That was an api that store3 had that is no longer needed.

@Nonnull
  V get(K key, Callable<? extends V> valueLoader) throws ExecutionException;

@digitalbuddha So looks like we do need to support this after all? Currently this is only used by FileSystemImpl. Are we planning to use this API anywhere else or even expose it in the Store API?

[yigit]

for xref: #89