Function scope_thread 

pub fn scope_thread(backend: Arc<dyn SecretBackend>) -> SecretsScope

From now until the guard drops, every SecretStore::for_app this thread creates keeps its secrets in backend, never the platform’s store. A host gives a participant it runs on its own thread (an agent) secrets apart from the host user’s this way. A store keeps the backend it was created with, wherever it is used later.