CMake

attempt at writing sketch column class #1145

Job	Run time
full-build (ubuntu-latest, "-DL0_SAMPLING")	1m 12s
full-build (ubuntu-20.04, "")	1s
full-build (ubuntu-latest, "-DNO_EAGER_DSU")	1m 11s
full-build (ubuntu-20.04, "-DNO_EAGER_DSU")	1s
full-build (ubuntu-latest, "")	1m 8s
full-build (ubuntu-20.04, "-DL0_SAMPLING")	1s
	3m 34s

Provide feedback