Support stopping and starting logging at runtime

Change-Id: If1e1b7119808d1f56e96efb71ea7000e0fa13fe8
diff --git a/aos/events/logging/uuid_test.cc b/aos/events/logging/uuid_test.cc
index d0320de..4ea351c 100644
--- a/aos/events/logging/uuid_test.cc
+++ b/aos/events/logging/uuid_test.cc
@@ -12,6 +12,8 @@
   LOG(INFO) << UUID::Random().string_view();
 
   EXPECT_NE(UUID::Random(), UUID::Random());
+  EXPECT_NE(UUID::Random(), UUID::Zero());
+  EXPECT_EQ(UUID::Zero(), UUID::Zero());
 }
 
 }  // namespace testing