Method getMutableArray

Fleece/Tree/MutableHashTree.cc:130–140

    MutableArray MutableHashTree::getMutableArray(slice key) {
        MutableArray result;
        insert(key, [&](Value value) -> Value {
            auto array = value.asArray();
            result = array.asMutable();
            if (!result)
                result = array.mutableCopy();
            return result;
        });
       return result;
    }

    MutableDict MutableHashTree::getMutableDict(slice key) {
        MutableDict result;