///
/// Identifiers can be used to retrieve a [`Job`] or [`JobMut`] through
/// [`Jobs::get`] and [`Jobs::get_mut`], respectively.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
pub struct JobId(ObjectId);
impl JobId {