Update JNI for contiguous_split packed results [skip ci]#7127

Merged

rapids-bot[bot] merged 9 commits intorapidsai:branch-0.18from jlowe:jni-packed

Feb 4, 2021

+337-110

Commits on Jan 12, 2021

Commits on Jan 14, 2021

Track row count explicitly to avoid manifesting table for row count
jlowe
committed

Commits on Feb 3, 2021

Merge branch 'branch-0.18' into jni-packed
jlowe
committed