Type Alias BackupRng 

type BackupRng = ReseedingRng<ChaCha20Core, Box<dyn RngCore + Send>>;

The type we’ve chosen to use for our backup Rng.

(We need to box this because the default JitterRng is unnameable.)

We use JitterRng to reseed a ChaCha20 core because it is potentially very slow.

Aliased Type

struct BackupRng(/* private fields */);