{{ size={arraySize} }} arraySize allocated arraySize _data {{ size={$T2} }} $T2 _data {{ size={_size} }} _size _size root next data [{key}, {value}] key value {{ size={_size} } _size comp _size root left right pair [{pair}] pair leftChild rightChild empty [{nodeContainer._data[node].pair}] nodeContainer._data[node].pair empty RefPtr {*object} object UniquePtr {*handle} handle