Empty typedef
Empty = $Empty
A generic empty message that you can re-use to avoid defining duplicated empty messages in your APIs.
A typical example is to use it as the request or the response type of an API method. For instance: service Foo { rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty); } The JSON representation for Empty is empty JSON object {}.
Implementation
typedef Empty = $Empty;