@Override
        public void entry(int idx, Inspector inspector) {
            if (inspector == guard) {
                return;
            }

            injectValue(new ArrayInserter(cursor), inspector, guard);
        }
Inject a slime sub-structure described by an Inspector into a slime
structure where the insertion point is described by an
Inserter. This will copy all the values represented by the
Inspector into the position described by the Inserter. Note that
this can be used to either copy data from one Slime structure to
another, or to copy data internally within a single slime
structure. If the Inspector contains the insertion point it will
only be expanded once to avoid infinite recursion.

@param inspector what to inject
@param inserter where to inject
vespajlib/src/main/java/com/yahoo/slime/Injector.java