use OffsetDateTime;
use cratePublishedCeremonyDefinition;
use crate;
/// Seal a handoff in the ceremony that is handing off.
///
/// The successor's published definition and the diff between the two
/// travel with the plan rather than being fetched by the decision: the
/// aggregate holds neither the catalogue nor the other definition, and
/// reading either would be I/O inside a pure decision. What stays in
/// the domain is what is done with them — the pin has to name the
/// bytes the plan was made against, evidence may only be carried onto
/// a step the successor actually declares, and only where the diff
/// says that step carries.