Function gen_test_blob_engine 

pub fn gen_test_blob_engine() -> Arc<ChunkingBlobEngine<Arc<dyn BlobStore>, Arc<dyn ChunkStore>>>

Available on crate features mocks only.

Returns a new BlobEngine. Should only be used for tests.

We wrap the underlying stores into Arc to match the signature of construct_services_from_configs, so the downcast in SnixStoreFs works.