The _MARKING_STATS_ define is used in the code to collect more detailed information about the marking cycle. Since this is a define that requires re-compilation to have any effect the code is not used by normal builds.
Thus, this is to be considered debug code. As such it should be removed from the normal code base and included back if it is needed for a debug session.
Thus, this is to be considered debug code. As such it should be removed from the normal code base and included back if it is needed for a debug session.