Function dylib_fixture 

pub fn dylib_fixture(plugin_dir: impl Into<PathBuf>) -> DylibFixtureBuilder

Start building a dylib fixture for the plugin crate at plugin_dir.

plugin_dir must contain a Cargo.toml with crate-type = ["cdylib"]. The resulting fixture caches the build across the current test binary process; subsequent calls with the same plugin_dir return the cached fixture without re-running cargo.