Deferred Dispose (maybe?)

## The Problem

When using EF Core with ASP.NET the typical way is to get a `DbContext` via DI, and this means inherently with a scoped lifetime: this, in turn, means that when the HTTP request finishes, the scope will be disposed.

Normally this is all good, but sometimes we need to let a query run after the HTTP request finishes.

An example of this scenario in which I run into (actually, some of my community members did) is when using EF with [FusionCache](https://github.com/ZiggyCreatures/FusionCache) with [Soft/Hard Timeouts](https://github.com/ZiggyCreatures/FusionCache/blob/main/docs/Timeouts.md) enabled: this feature allows for a slow query that is taking too much time to be finished in the background, while temporarily returning the stale value, to allow for faster response times without missing on a cache update.

A different but similar feature that has a similar behavior is [Eager Refresh](https://github.com/ZiggyCreatures/FusionCache/blob/main/docs/EagerRefresh.md).

For example here's [an issue](https://github.com/ZiggyCreatures/FusionCache/issues/21) opened for this.

## The Current Solution (Workaround?)

The solution highlighted in the original consist in changing the way to use EF, from a scoped `DbContext` automatically injected via DI to using `IServiceScopeFactory` and manually create scopes.

It did work, and seemingly well, but it doesn't look spectacular so I'm looking for potential alternatives.

## A Possible Solution

Something different I've been thinking about is the concept of deferred scopes: by enabling such a feature it would be possible to defer the actual disposal of a `DbContext`, so that when calling `Dispose()` (either manually or automatically by ASP.NET's DI scope handling) the underlying disposal logic will be executed ONLY if there is no query being executed.

If instead there's a query still running, the disposal will be executed as soon as the query will complete, either successfully or by failing/throwing.

I'm not sure this is the way to go, maybe it's a stupid idea and there may be potential consequences for acting in this way, but this is the reason I'm opening this issue: to talk about such possibility and see if something comes up.

Thanks in advance for your time!