AFAIK the writes and reads are done only from the same process, so the long term storage will apply only if the current process is hibernated. When you write something and then read it, it's immediate, because the writes and reads are also updating the current process's state in memory.

For another process (e.g. another DO or another worker) to access the data, they need to go through the DO which "contains" the data, so they'd be making a RPC or a HTTP request to the DO, and they'd get the latest information.

+ the hibernation happens after x seconds of inactivity, so it feels like the only time a data write to be unavailable as expected would be when the DO or worker crashes right after a write.