Change Gist visibility via API?

[stigzler]

Hi folks. I'm using the .net Octokit.

I can't find any way to update a Gist's visibility (i.e. between Public and Private). The relevant classes seem to be:

GistFileUpdate: Content, NewFilename
GistUpdate: Description, Files(DICT: string(orig filename), GistFileUpdate)
GistClient.Edit: GistId, GistUpdate

However, there appears to be no way to update the Public property of an existing Gist. You can of course set this when you create a new gist, but is there no way to update an existing one form the API? I'm likely missing something really obvious?