Kafka schema registration and reconcilliation

comic.txt

   ,----------.                         ,-----------------.
   | Producer |------------------------>| Schema Registry |
   `----------'                         `-----------------'
   Hi. Can I register a schema S1?
   It looks like this {avsc}
   
   ,----------.                         ,-----------------.
   | Producer |<------------------------| Schema Registry |
   `----------'                         `-----------------'
                                        Sure. This looks
                                        compatible with what
                                        we had before.
                                        Let's use ID 1234.

   ,----------.                         ,---------.
   | Producer |------------------------>|  Kafka  |
   `----------'                         `---------'
   I am producing a message
   ┌─────┬────────────┐
   |Byte | Content    |  
   ├─────┼────────────┤  
   |1    | Magic byte | 
   ├─────┼────────────┤  
   |2..5 | Schema ID  | "(= 1234)"
   ├─────┼────────────┤ 
   |6+   | Message    | 
   └─────┴────────────┘  
                                        ...ok
        

                     LATER...


   ,----------.                         ,---------.
   | Consumer |------------------------>|  Kafka  |
   `----------'                         `---------'
   Do you have a
   message for me?
                                        yes!
                                        it is
                                        ┌─────┬────────────┐
                                        |Byte | Content    |  
                                        ├─────┼────────────┤  
                                        |1    | Magic byte | 
                                        ├─────┼────────────┤  
                                        |2..5 | "1234"     |
                                        ├─────┼────────────┤ 
                                        |6+   | Message    | 
                                        └─────┴────────────┘  

   ,----------.                         ,-----------------.
   | Consumer |------------------------>| Schema Registry |
   `----------'                         `-----------------'
   I've received a message
   with schema ID 1234.
   Can you tell me what that is?
   What is this WRITER SCHEMA?

   ,----------.                         ,-----------------.
   | Producer |<------------------------| Schema Registry |
   `----------'                         `-----------------'
                                        Yes. I recognise that
                                        ID. It is this AVSC.
                                        Here you go.

   ,----------.
   | Consumer |
   `----------' 
   "Hmm. I have a READ SCHEMA in my own memory."
   But I don't recognise this WRITER SCHEMA.


   ,----------.                         ,-----------------.
   | Consumer |------------------------>|   AVSC Library  |
   `----------'                         `-----------------'
   Can you tell me how to
   RECONCILE these two schemas?

                                        Yes. As it meets the
                                        compatibilty requirement, 
                                        we can read it like so.
                                        Skip these fields. Use
                                        these default values.

   ,----------.
   | Consumer |
   `----------' 
   Alright, now I know how to process this message!