Defined in github.com/google/google-api-go-client/youtube/v3/youtube-gen.go
Set: Uploads a custom video thumbnail to YouTube and sets it for a
// "relevance" - Resources are sorted based on their relevance to the
// search query. This is the default value for this parameter.
// "title" - Resources are sorted alphabetically by title.
// "videoCount" - Channels are sorted in descending order of their
// number of uploaded videos.