apply
Persist one quarantine decision.
QuarantineDecision.Quarantined.proposition is already the QUARANTINED copy carrying its reason and the status it came from; a policy built it and wrote nothing. This is the write.
An implementation announces the transition to whatever listener it was given as a com.embabel.dice.common.PropositionStatusChanged, so a consumer watching the proposition lifecycle hears about a quarantine the way it hears about any other status move.
Return
The saved proposition.
Parameters
decision
What the policy decided.