Merge PR #33771 into octopus

* refs/pull/33771/head:
	common/ceph_timer: Pass reference to waited time on stack
	common/ceph_timer: Add test
	common/ceph_timer: Use unique_function, allowing noncopyable events
	common/ceph_timer: Couple cleanups
	common/ceph_timer: Fix namespaces
	common/ceph_timer: Add missing includes
	common/ceph_timer.h: Don't indent contents of a namespace

Reviewed-by: Sage Weil <sage@redhat.com>