Private API

Not intended to be imported outside the library.

• _download
  • download_and_install_build()
• _io
  • clear_build_dir()
  • copy_and_install_zip()
  • copy_build_files()
  • copytree_to_build()
  • set_installed_path_read_only()
• _package
  • BuildPackageVersion
  • preserve_build_attributes()
• _pip
  • install_pip_package()