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• If a cluster contains nodes of only version, then the joining node can be greater/less than this version by up to 1 minor version.
• If a cluster contains nodes of two versions, then joining node version must be one of them.

Message

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serialization framework

There should be one serialization framework for communication and discovery protocol. 

1. MessageWriter, MessageReader logic is depends on a remote IgniteProductVersion.
2. Message#writeTo, Message#readFrom is auto-generated and stored separately from Message DTO classes classes.
3. Add Message#writeObject - for serializing Objects (java functions, and user objects):
   1. MessageWriter for communication protocol use BinaryMarshaller
   2. MessageWriter for discovery protocol use JdkMarshaller
4. Message fields contain:
   1. primitive classes.
   2. known collections.
   3. POJO - that are other Message.
   4. Users classes and java functions (e.g. ComputeJob).
   5. byte[] fields (objects serialized externally) must be avoided as much as possible, because their compatibility can't be guaranteed.
5. Order of fields in Message is fixed with @Order annotation.
6. Add  @Since, @Until  annotations for Message classes and fields.

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