DEFINE_SCRUB_EVENT
DEFINE_SCRUB_EVENT(xchk_start);
DEFINE_SCRUB_EVENT(xchk_done);
DEFINE_SCRUB_EVENT(xchk_deadlock_retry);
DEFINE_SCRUB_EVENT(xchk_dirtree_start);
DEFINE_SCRUB_EVENT(xchk_dirtree_done);
DEFINE_SCRUB_EVENT(xrep_attempt);
DEFINE_SCRUB_EVENT(xrep_done);