通过在***响应***类型前插入`stream`关键字,可以指定一个服务器端的流方法。``` // Obtains the Features available within the given Rectangle. Results are // streamed rather than returned at once (e.g. in a response message with a // repeated field), as the rectangle may cover a large area and contain a // huge number of features. rpc ListFeatures(Rectangle) ret...