The delegate's own copy of the controlling document (live: mutating it mutates the delegate).
The controller's XID.
The reference of the controller's XID.
The permissions (live).
The allowed privileges (a copy).
The denied privileges (a copy).
StaticfromA delegate controlled by a copy of controller taken now (as the
reference's Delegate::new clones it): a later change to the
caller's document is not seen. No permissions unless given.
Empties both sets.
The controller's envelope, wrapped, with the permissions.
StaticfromA delegate from its envelope: the permissions, then the unwrapped
controller parsed with XIDDocument.fromEnvelope. A sibling failure
is EnvelopeParsing.
Same controller document and permissions — as the reference's equality.
A deep copy.
A delegate: a controller document and the permissions this document grants it.