Added FlushIndexTask to flush documents at index thread level.#2349

Open

balmukundblr wants to merge 2 commits intoapache:masterfrom

balmukundblr:benchmark_explicit_flush

Commits on Feb 10, 2021

Added FlushIndexTask to flush data at index thread level.
balmukundblr
committed

Commits on Mar 2, 2021

Removed commented code.Also, changed the num of thread to 8 to work with typical box.
balmukundblr
committed