Probable major bug in private filterItemsAsync() method.

[mecoFarid]

filterItemsAsync() always checks for a new filter. If filter parameters haven't been changed then filtering will be omitted here:

private synchronized void filterItemsAsync(@NonNull List<T> unfilteredItems) {
        // Omitted for brevity 
        if (hasFilter() && hasNewFilter(mFilterEntity)) { //skip when filter is unchanged

        }
    }

Steps to reproduce:
Let's take a simple situation where each item has a status field called isSent.

1. Add a few items to the adapter where isSent = false
2. Apply filter where only items with isSent = false should be visible
3. Change status of any single item item to isSent = true and the call FlexibleAdapter.filterItems()
4. Since the filter itself hasn't changed, the filtering will, simply, be omitted