* Refactor Segment Granularity
* Beginning of one granularity
* Copy the fix for custom periods in segment-grunalrity over here.
* Remove the custom serialization for now.
* Compilation cleanup
* Reformat code
* Fixing unit tests
* Unify to use a single iterable
* Backward compatibility for rolling upgrade
* Minor check style. Cosmetic changes.
* Rename length and millis to duration
* CR feedback
* Minor changes.
This also involved some other test changes:
- Added a factory.mergeRunners step to AggregationTestHelper's groupBy chain, since the v2
engine does merging there.
- Changed test byteBuffer pools from on-heap to off-heap to work around
https://github.com/DataSketches/sketches-core/pull/116 for datasketches tests.
praveev
Gian Merlino
Jonathan Wei
Keuntae Park