What are spinoff and spinouts in magit

Let's assume the following working git tree:

* 465318a (HEAD -> foobar) helloworld
* f4dd687 (master) init

A magit-branch-spinoff will create a new branch foobaz which takes foobar's place, and foobar will be moved to the branch's upstream:

* 465318a (HEAD -> foobaz) helloworld
* f4dd687 (master, foobar) init

A magit-branch-spinoff will perform the same operations of magit-branch-spinoff, however we'll stay on the current branch.

* 465318a (foobaz) helloworld
* f4dd687 (HEAD -> foobar, master) init