> Objects well-suited to transfer would be shallow mutable structures with immutable data "underneath". Immutable data can be shared, so they'd be ignored by the transfer logic.

How often are data structures designed like this in Ruby?

> Another approach likely to be common would be not transferring objects at all, but sending proxy objects to other guilds which transparently marshal method invocations between those guilds and the object's home guild.

What if said “home guild” ends up overburdened with requests coming from all over the place?

> This is easy. You just run the transfer operation with the guild's mutex locked.

You mean both the sender and the receiver's mutexes? I'm worried about the receiver being able to observe partial transfers.