The way we build this attribute binding, there is no single
entity to handle all attribute bindings. Thus the only way
to detect a missing binding is when none of the binding layers
was able to handle a given INS verb
since we're moving elements around to apply the diff,
dangerous situation might arise in case anyone takes a copy
of the mutator. Thus we effectively limit the possible
usage pattern and only allow to build an anonymous
TreeMutator subclass through the Builder-DSL.
The concrete "onion layers" of the TreeMutator are now limited
- to be created by the chaining operations of the Builder DSl
- to be moved into target location, retaining ownership.
the concern is for the structure of the builder to be
incomprehensible and completely buried within the
implementation details of the various binding layers
