[PATCH v2 2/3] graph: add support for node free API

[Huichao Cai]

By the way, I don't know where to consult about this issue at the moment.
Please forgive me for discussing this issue here. Can we set up a chat box on this
page instead of having to comment through email or git send email? Many email clients
cannot set the In Reply To header or do not currently have a git send email environment,
which is not conducive to the timeliness and convenience of comments.