// option 1
arkplugin.NewSimpleServer().
  RegisterObjectStores(map[string]func() cloudprovider.ObjectStore{
    "aws": setupAws,
    "azure": azure.NewObjectStore,
    "gcp": setupGcp,
  }).
  RegisterBlockStores(map[string]func() cloudprovider.BlockStore{
    "aws":   aws.NewBlockStore,
    "azure": azure.NewBlockStore,
    "gcp": abc,
  }).
  Serve()

// option 2
arkplugin.NewSimpleServer().
  RegisterObjectStore("aws", xxx).
  RegisterObjectStore("azure", azure.NewObjectStore).
  RegisterObjectStore("gcp", yyy).
  RegisterBlockStore("aws", aws.NewBlockStore).
  RegisterBlockStore("azure", azure.NewBlockStore).
  RegisterBlockStore("gcp": zzz).
  Serve()

// option 3
arkplugin.NewSimpleServer().
  Register(PluginKindObjectStore, "aws", asdf).
  Register(PluginKindObjectStore, "gcp", gdgs).
  Serve()

// option 4
arkplugin.NewSimpleServer().
  RegisterObjectStores(
    "aws", setupAws,
    "gcp", setupGcp,
    "azure", setupAzure,
  ).
  RegisterBlockStores(
    ...
  ).
  Serve()