ValvePython.steam/protobufs/test_messages.proto

syntax = "proto2";

message ComplexProtoMessage {
	message InnerMessage {
        optional string text = 1;
        repeated uint32 numbers = 2;
	}
	message InnerBuffer {
        message Flags {
            optional bool flag = 1;
        }

		optional bytes data = 1;
        repeated .ComplexProtoMessage.InnerBuffer.Flags flags = 2;
	}

    optional uint32 number32 = 1;
    optional uint64 number64 = 2;

    repeated uint32 list_number32 = 3;
    repeated uint64 list_number64 = 4;

	repeated .ComplexProtoMessage.InnerMessage messages = 5;
	repeated .ComplexProtoMessage.InnerBuffer buffers = 6;
}