From what I understand these features are a nice way to implement a serverless Actor Model. I was surprised to see no reference to it on the CloudFlare page.
Possibly. We did not base the design (or name) of Durable Objects on any other product we were aware of (except arguably Sandstorm.io, which was my startup before joining Cloudflare). I haven't looked closely at Azure Durable Functions.
We actually did call this product "Actors" internally for a long time, but we found that people who had done previous Actor Model work (e.g. in Erlang) ended up more confused than enlightened by this name, so we ditched it.
https://dotnet.github.io/orleans/Documentation/index.html