code: def always_forkserver_on_unix():
      if os.name == "nt":
          return
  
      # Full background: https://github.com/pybind/pybind11/issues/4105#issuecomment-1301004592
      # In a nutshell: fork() after starting threads == flakiness in the form of deadlocks.
      # It is actually a well-known pitfall, unfortunately without guard rails.
      # "forkserver" is more performant than "spawn" (~9s vs ~13s for tests/test_gil_scoped.py,
      # visit the issuecomment link above for details).
      # Windows does not have fork() and the associated pitfall, therefore it is best left
      # running with defaults.
      multiprocessing.set_start_method("forkserver")
  
imports: import contextlib
  import difflib
  import gc
  import multiprocessing
  import os
  import re
  import textwrap
  import traceback
  import pytest
label_desc: Use image node_id 1 for calling a global function with example usage: always_forkserver_on_unix() without return types