common: C++ RateKeeper (#29374)

* c++ RateKeeper

* add to files_common

* use util::random_int

* improve monotor_time

* remove ~ratekeeper
old-commit-hash: 3eef63af9b4f4a25bc4c3a0d6ad450bba9f62205

common/tests/.gitignore

@@ -1,2 +1,3 @@
+test_ratekeeper
 test_util
 test_swaglog

common/tests/test_ratekeeper.cc

@@ -0,0 +1,17 @@
+#define CATCH_CONFIG_MAIN
+#include "catch2/catch.hpp"
+#include "common/ratekeeper.h"
+#include "common/timing.h"
+#include "common/util.h"
+
+TEST_CASE("RateKeeper") {
+  float freq = GENERATE(10, 50, 100);
+  RateKeeper rk("Test RateKeeper", freq);
+  for (int i = 0; i < freq; ++i) {
+    double begin = seconds_since_boot();
+    util::sleep_for(util::random_int(0, 1000.0 / freq - 1));
+    bool lagged = rk.keepTime();
+    REQUIRE(std::abs(seconds_since_boot() - begin - (1 / freq)) < 1e-3);
+    REQUIRE(lagged == false);
+  }
+}