Spike: Read your own writes across replicas

[mkysel]

This is an extension of #418 and #415.

The above mentioned issues should guarantee that a client will see it's commits when read from the same originator. This does not necessarily hold for multiple nodes in a decentralized system.

Whatever the solution is, it will have to leak to the client implementation.

We can probably expand the use of the last-seen Cursor. Or possibly the dependencies.

This has implications on the client. A write can take infinitely long to appear on another node.

What does the client do if it does not appear within a timeout (30s?).

What does the client do if the message is lost forever (due to catastrophic failure)?

This spike probably intersects with censorship resistance.