syntax="proto2";
package unit;

message AddRequest {
	required int32 a = 1;
	required int32 b = 2;
};

message AddResponse {
	required int32 c = 1;
};

message SubstrRequest {
	required string str = 1;
	required int32 idx = 2;
	optional int32 length = 3;
};

message SubstrResponse {
	required string str = 1;
};

service TestPB {
      rpc Add(AddRequest) returns (AddResponse);
      rpc Substr(SubstrRequest) returns (SubstrResponse);
};