SetTimestamp

pub const SetTimestamp = union(enum) {
    /// Leave the existing timestamp unmodified.
    unchanged,
    /// Set to current time using `Io.Clock.real`.
    now,
    /// Set to provided timestamp using `Io.Clock.real`.
    new: Io.Timestamp,

    /// Convenience for interacting with `Stat`, in which `null` indicates `unchanged`.
    pub fn init(optional: ?Io.Timestamp) SetTimestamp {
        return if (optional) |t| .{ .new = t } else .unchanged;
    }
}