Function turbo_backing_storage 

pub fn turbo_backing_storage(
    base_path: &Path,
    version_info: &GitVersionInfo<'_>,
    is_ci: bool,
    is_short_session: bool,
) -> Result<(TurboBackingStorage, StartupCacheState)>

Creates a BackingStorage to be passed to TurboTasksBackend::new.

Information about the state of the on-disk cache is returned using StartupCacheState.

This is the fastest most-tested implementation of BackingStorage, and is normally returned by default_backing_storage.