Google_Protobuf_Api

Interfaces are also described as “protocol buffer services” in some contexts, such as by the “service” keyword in a .proto file, but they are different from API Services, which represent a concrete implementation of an interface as opposed to simply a description of methods and bindings. They are also sometimes simply referred to as “APIs” in other contexts, such as the name of this message itself. See https://cloud.google.com/apis/design/glossary for detailed terminology.