Introduced :c:func:`PyUnstable_WritePerfMapEntry`, :c:func:`PyUnstable_PerfMapState_Init` and
:c:func:`PyUnstable_PerfMapState_Fini`. These allow extension modules (JIT compilers in
particular) to write to perf-map files in a thread safe manner. The
:doc:`../howto/perf_profiling` also uses these APIs to write
entries in the perf-map file.