feat(proto): add proto message trait

proto/src/message/mod.rs

@@ -1 +1,2 @@
 pub mod primitive;
+pub mod proto_message;

proto/src/message/proto_message.rs

@@ -0,0 +1,5 @@
+pub trait ProtoMessage: Sized {
+    fn variant(&self) -> u8;
+    fn serialize(&self) -> anyhow::Result<Vec<u8>>;
+    fn deserialize(variant: u8, data: &[u8]) -> anyhow::Result<Self>;
+}