Connection pool queue is confusing to work with because half the methods refer to the connection pool rather than the queue, which is a queue of available connections only. The docs for each attribute/method should clearly state whether the attribute/method refers to the queue or the pool, where appropriate.

Additionally since we must leave some of the confusing methods in place for compatibility reasons, it will be good to have invariant checks using our lint framework to ensure the state is internally consistent. This becomes more important when we try to close connections upon enqueueing as per 1319.