Method handle_message

examples/batch_insert_mysql.rs:105–112

(&mut self, msg: User)

    async fn terminate(&mut self) {}

    async fn handle_message(&mut self, msg: User) ->  ProcResult<User> {

        // ordering - partitioning based on 'fullname'
        let pk = msg.fullname.clone();

        // Dispatch to Batcher
        ProcResult::Dispatch(msg, pk)
    } 
}