Add Map of Deque

[webmaster128]

Maps and Deques are great. But how to combine them? Both a list of maps and a map of lists are interesting.

In order to get a map of Deques I currently have to use a workaround like this:

/// Add an element to the unprocessed drand jobs queue of this round
pub fn jobs_queue_enqueue(storage: &mut dyn Storage, round: u64, value: &Job) -> StdResult<()> {
    let prefix = format!("drand_jobs_{:0>10}", round);
    Deque::new(&prefix).push_back(storage, value)
}

/// Remove an element from the unprocessed drand jobs queue of this round
pub fn jobs_queue_dequeue(storage: &mut dyn Storage, round: u64) -> StdResult<Option<Job>> {
    let prefix = format!("drand_jobs_{:0>10}", round);
    Deque::new(&prefix).pop_front(storage)
}

I.e. I have to create new Deques on the fly after composing the correct key. It works but does not look beautiful. Wouldn't it be great to make a DequeMap instead which has all the power of key composability of a Map plus many storage items (a deque) per key? That would allow maps of stacks as well as maps of queues.

[TrevorJTClarke]

Not sure if this is exactly what you're hoping for, but maybe another example/inspiration: https://docs.rs/near-sdk/3.1.0/near_sdk/collections/struct.TreeMap.html
This was very helpful for using things like floor_key