Typically in databases, transaction logs are a resilience measure if something bad happens that the database must be restored—or to keep a replica up to date. The principle is fairly simple: the log represents a timeline of commands that have been executed in this exact order. Thus, to recreate that final state of a database, it is necessary to start with the oldest entry and apply every transaction that follows in that very order.
You may have caught how that fits the capabilities of a linked list nicely. So, what is missing from the current implementation?
The ability to remove elements starting at the front.
Since the entire data structure resembles a queue, this function is going to be called pop, as it's the typical name for this kind of operation. Additionally, pop will consume the item that was returned, making the list a single-use structure. This makes sense, to avoid replaying anything twice!
This looks a lot more complex than it is: the interior mutability...