Minor, added Node::null
Added
Node::nullplaceholder that avoids the tricky memory management ofNode::mockthat can lead to memory leaks. Really a poor substitute for the betterOption<Node>type with aNonevalue, which is recommended instead.
Node::null placeholder that avoids the tricky memory management of Node::mock that can lead to memory leaks. Really a poor substitute for the better Option<Node> type with a None value, which is recommended instead.