Proof of concept showing how easy this is to change. Would close #923 if we like it. Considerations:

• We should get a better sense than I did in Make page tokens shorter #923 of how much of an improvement this is in the real world
• Should we try compression also/instead?
• Do we need to rev the PaginationVersion? Currently, Nexus deploys involve shutting down all nodes, so the problem of old and new formats being used at the same time isn't likely to be a big problem, plus we'd have to add logic for handling both formats
  

  dropshot/dropshot/src/pagination.rs

  Lines 387 to 404 in 6b41086

  	/// Version for the pagination token serialization format
  	///
  	/// This may seem like overkill, but it allows us to rev this in a future version
  	/// of Dropshot without breaking any ongoing scans when the change is deployed.
  	/// If we rev this, we might need to provide a way for clients to request at
  	/// runtime which version of token to generate so that if they do a rolling
  	/// upgrade of multiple instances, they can configure the instances to generate
  	/// v1 tokens until the rollout is complete, then switch on the new token
  	/// version. Obviously, it would be better to avoid revving this version if
  	/// possible!
  	///
  	/// Note that consumers still need to consider compatibility if they change their
  	/// own `ScanParams` or `PageSelector` types.
  	#[derive(Copy, Clone, Debug, Deserialize, JsonSchema, PartialEq, Serialize)]
  	#[serde(rename_all = "lowercase")]
  	enum PaginationVersion {
  	V1,
  	}