Guidelines:

Should include

• What does the versioning protocol achieve? E.g., allows a router to lazily discover that its routing cache is stale
• What types of events cause a routing cache to be stale?
• What are special version conventions we use? 0,0|0 for unsharded, 0,0|epoch for no chunk, 0,0|MAX for ignored

Code references

• Where shardVersions are stored in a router's cache
• An example of how shardVersion is attached in an egress message
• Where shardVersions are parsed in the ServiceEntryPoint and put on the OperationShardingState
• Where shardVersions are stored in a shard's filtering cache
• The checkShardVersion method on a shard