769f35fc0f
This is a sychronizing primitive that is similar to a latch, but a thread must count down with an identifier. It will be used to make sure the boot complete, uid map, and all pullers signals are received before triggering the bucket split. The latch's countDown operation takes in a string identifier, so that if the same operation happens twice, it is only counted once. Bug: 144099206 Test: atest statsd_test Change-Id: I261a3e50eabbc4998ca30ddf2d67a9a1e788911e