Request : LiveData observing Query.count instead of Query.find

Hi,

I'd like to use LiveData to observe the number of items resulting of a given query (the equivalent of Query.count() or Query.findLazy().size()).

As of v2.4.0, LiveData only calls Query.find, so the only implementation I came up with is not optimal at all

// Get all results as objects
// NB : db.queryContentSearch is a Query<Content>
ObjectBoxLiveData<Content> livedata = new ObjectBoxLiveData<>(db.queryContentSearch(query, metadata, favouritesOnly));

// Instanciated objects are useless because we just actually count them !
MediatorLiveData<Integer> result = new MediatorLiveData<>();
result.addSource(livedata, v -> result.setValue(v.size()));
return result;

=> Would it be possible in future versions to build LiveData's that observe Query.count ?
Or have I overlooked a feature that already exists ?

Thanks a lot for your help,
-Robb

首先检查当前调用 Query.find 的 LiveData 行为，然后比较 issue 中描述的 Query.count 和 Query.findLazy API。完成的标准是：LiveData 选项可以观察查询的数量，而无需将所有结果对象具体化，并且会在查询结果发生变化时更新。