### What needs to get done * Ensure all plugins use `ProjectInfo.parallel_build_count` if possible * Update plugin documentation to mention if the plugin supports parallel builds The `rust` and `scons` plugins support parallel builds but do not use it. Other plugins need to be checked. ### Why it needs to get done To speed up build times or to limit resource utilization of a build source: https://github.com/canonical/craft-parts/issues/631#issuecomment-1908500081