What types of service methods does gRPC support?

gRPC supports four types of service methods:

1. Unary RPC: Client sends one request, server returns one response

rpc GetUser(UserRequest) returns (User);

2. Server Streaming RPC: Client sends one request, server returns a stream of responses

rpc ListUsers(ListUsersRequest) returns (stream User);

3. Client Streaming RPC: Client sends a stream of requests, server returns one response

rpc CreateUsers(stream User) returns (CreateUsersResponse);

4. Bidirectional Streaming RPC: Both client and server send streams of messages

rpc Chat(stream ChatMessage) returns (stream ChatMessage);