set-breakables in drscheme:unit:frame

Calling this method with a thread and a custodian means that the next time the break button is clicked, it will either break the thread or shutdown the custodian.

See also get-breakables.

• (send a-drscheme:unit:frame set-breakables thread custodian) -> void
     thread : (union thread #f)
     custodian : (union custodian #f)