simplify multithreaded variant
simplify multithreaded variant

kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground,kkirstein/proglang-playground