Import takes 800ms due to pkg_resources

[FabriceSalvaire]

Here profile of import markdown

         1234363 function calls (1229528 primitive calls) in 0.933 seconds

   Ordered by: cumulative time

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
    109/1    0.001    0.000    0.933    0.933 {built-in method builtins.exec}
        1    0.000    0.000    0.933    0.933 devel/profile-import.py:1(<module>)
    124/1    0.001    0.000    0.933    0.933 <frozen importlib._bootstrap>:978(_find_and_load)
    124/1    0.000    0.000    0.933    0.933 <frozen importlib._bootstrap>:948(_find_and_load_unlocked)
    118/1    0.001    0.000    0.933    0.933 <frozen importlib._bootstrap>:663(_load_unlocked)
     87/1    0.000    0.000    0.933    0.933 <frozen importlib._bootstrap_external>:722(exec_module)
    151/1    0.000    0.000    0.904    0.904 <frozen importlib._bootstrap>:211(_call_with_frames_removed)
        1    0.000    0.000    0.904    0.904 .../site-packages/markdown/__init__.py:21(<module>)
        1    0.000    0.000    0.895    0.895 .../site-packages/markdown/core.py:21(<module>)
        1    0.000    0.000    0.800    0.800 .../site-packages/pkg_resources/__init__.py:16(<module>)
        2    0.000    0.000    0.708    0.354 .../site-packages/pkg_resources/__init__.py:3174(_call_aside)
        1    0.000    0.000    0.708    0.708 .../site-packages/pkg_resources/__init__.py:3191(_initialize_master_working_set)
       36    0.003    0.000    0.452    0.013 .../site-packages/pkg_resources/__init__.py:611(add_entry)
     2760    0.006    0.000    0.428    0.000 .../site-packages/pkg_resources/__init__.py:2005(find_on_path)
      454    0.000    0.000    0.256    0.001 .../site-packages/pkg_resources/__init__.py:3218(<genexpr>)
      453    0.002    0.000    0.255    0.001 .../site-packages/pkg_resources/__init__.py:2717(activate)
     3297    0.010    0.000    0.232    0.000 .../site-packages/pkg_resources/__init__.py:2159(_handle_ns)
        1    0.000    0.000    0.231    0.231 .../site-packages/pkg_resources/__init__.py:569(_build_master)
        1    0.000    0.000    0.230    0.230 .../site-packages/pkg_resources/__init__.py:556(__init__)
      453    0.002    0.000    0.228    0.001 .../site-packages/pkg_resources/__init__.py:2258(fixup_namespace_packages)
     5420    0.013    0.000    0.203    0.000 .../site-packages/pkg_resources/__init__.py:2092(distributions_from_metadata)
     3287    0.005    0.000    0.199    0.000 <frozen importlib._bootstrap_external>:421(_find_module_shim)
       18    0.000    0.000    0.199    0.011 .../site-packages/pkg_resources/__init__.py:1979(_by_version_descending)
       18    0.010    0.001    0.199    0.011 {built-in method builtins.sorted}
     3732    0.042    0.000    0.195    0.000 <frozen importlib._bootstrap_external>:1356(find_spec)
     3287    0.002    0.000    0.185    0.000 <frozen importlib._bootstrap_external>:1339(find_loader)
     2710    0.005    0.000    0.145    0.000 .../site-packages/pkg_resources/__init__.py:1994(_by_version)
     2710    0.005    0.000    0.130    0.000 .../site-packages/pkg_resources/__init__.py:2000(<listcomp>)
     2726    0.013    0.000    0.128    0.000 .../site-packages/pkg_resources/__init__.py:2546(from_location)
     8240    0.009    0.000    0.125    0.000 .../site-packages/pkg_resources/_vendor/packaging/version.py:24(parse)
    11080    0.046    0.000    0.112    0.000 .../site-packages/pkg_resources/_vendor/packaging/version.py:198(__init__)
       87    0.001    0.000    0.112    0.001 <frozen importlib._bootstrap_external>:793(get_code)
    35/19    0.000    0.000    0.100    0.005 {built-in method builtins.__import__}

[FabriceSalvaire]

pkg_resources import should be move to core.py:Markdown.build_extension

[waylan]

PRs are welcome.