This trait is for bloom, not crds.
Slightly better would be to put it in the SDK so that the trait
implementations could go into hash and pubkey, but if we don't
want compatibility constraints, this is the next best thing.
* Cluster Replicated Data Store
Separate the data storage and merge strategy from the network IO boundary.
Implement an eager push overlay for transporting recent messages.
Simulation shows fast convergence with 20k nodes.