I'm trying to name a module in a piece of software. The module
guarantees the delivery of messages sent on a network connection
that's only available intermittently, and makes no guarantees about
when the delivery might be.
The closest technical term for this is reliable messaging:
Reliable messaging is the concept of communicating messages across an
unreliable infrastructure whilst being able to make certain guarantees
about the successful transmission of the messages; for example, that
if the message is delivered, it is delivered at most once, or that all
messages successfully delivered arrive in a particular order.
The caveat is that reliable messaging assumes you can provide some guarantee of the message delivery process.
Now, I don't know of a single word that would define this, but as it is an accepted term in the software networking domain, you may say "the module implements reliable messaging".
I initially thought of suggesting measured because it concentrates on the slowness of it, but I believe in your case you shouldn't concentrate on the slow part (because this is not really a defining factor of your module), the key component is the guarantee which may result in the slowness of the system.
In other words, the slowness may not happen, as long as the guarantee is enforced.