func tree_to_chan(tree *llrb_tree.Tree, order int) (channel chan Item) {
channel = make(chan Item, tree.Len())
for item := range tree.Iter(order) {
channel <- item
}
close(channel)
return channel
}
func tree_to_slice(tree *llrb_tree.Tree, order int) (slice []Item) {
slice = make([]Item, tree.Len())
var i int
for item := range tree.Iter(order) {
slice[i] = item
i++
}
return
}