why not visit items "in-order"?

[eroller]

the find* and visit* methods should return intervals "in-order" (i.e. left tree Intervals -> current vector Intervals -> right tree Intervals). This would guarantee the returned Intervals are sorted by start position when the stored Intervals are non-overlapping. Also, it would be nice to have an iterator interface over the tree which would allow users to use some common algorithms more efficiently than having to first create a vector. They could also modify the values stored in the IntervalTree rather than just copying them.

https://github.com/ekg/intervaltree/blob/master/IntervalTree.h#L166-L178