void sgen_memgov_collection_start (int generation) MONO_INTERNAL;
void sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count) MONO_INTERNAL;
void sgen_memgov_collection_start (int generation) MONO_INTERNAL;
void sgen_memgov_collection_end (int generation, GGTimingInfo* info, int info_count) MONO_INTERNAL;