Function revert_checkpoint 

pub fn revert_checkpoint<T, V>(
    container_root: impl AsRef<Path>,
    request: &CheckpointRevertRequest,
    select_timestamp: T,
    validate_source: V,
) -> Result<(CheckpointReceipt, ResolvedProjectGeneration), GfError>
where
    T: FnOnce() -> Result<i64, GfError>,
    V: FnOnce(&ResolvedProjectGeneration) -> Result<(), GfError>,

Publish a complete-workspace restoration as a new child generation.