some questions about the implementation of intervalTree

[liyue201]

etcd/pkg/adt/interval_tree.go

Line 237 in b852e37

sentinel *intervalNode

i don't think the implementation of intervalTree is good. why don't use go nil as NIL leaf node. i have saw this issue #10881 (comment)

i not think the reason is go nil, but this function

etcd/pkg/adt/interval_tree.go

Line 362 in b852e37

func (ivt *intervalTree) deleteFixup(x *intervalNode) {

it does not supports nil parameter.

[spzala]

@liyue201 for code related changes/proposals, I would suggest to create PR for a better discussion and review. Hope makes sense. I am closing this issue but please feel free to create a PR or reopen this if you want. Thanks!