Breaks this node into two nodes at the specified
offset, keeping both
in the tree as siblings. After being split, this node will contain all
the content up to the
offset point. A new node of the same type, which
contains all the content at and after the
offset point, is returned.
If the original node had a parent node, the new node is inserted as the
next sibling of the original node. When the
offset is equal to the length
of this node, the new node has no data.
Copyright Lodovico Giaretta 2016 --