func (ivt *IntervalTree) Union(inIvt IntervalTree, ivl Interval) {
	f := func(n *IntervalValue) bool {
		ivt.Insert(n.Ivl, n.Val)
		return true
	}
	inIvt.Visit(ivl, f)
}
func (ivt *IntervalTree) Union(inIvt IntervalTree, ivl Interval) {
	f := func(n *IntervalValue) bool {
		ivt.Insert(n.Ivl, n.Val)
		return true
	}
	inIvt.Visit(ivl, f)
}
func ( ivt * IntervalTree ) Union ( inIvt IntervalTree , ivl Interval ) { f := func ( n * IntervalValue ) bool { ivt . Insert ( n . Ivl , n . Val ) return true } inIvt . Visit ( ivl , f ) }
// Union merges a given interval tree into the receiver.
Union merges a given interval tree into the receiver .