when using filter and adding items,
filtered_get processing item will cause item order errors by adding
late ordered item into the prev block before adding prev ordered item.
normally items are internally processed by queue_process(),
order of sd->queue list, and will be added into the blocks.
N-th item -> M-th block
(N+1)-th item -> (M+1)-th block
but when using filter,
item_filtered_get() want processing item regardless of queuing orders,
so (N+1)-th item is added in M-th block before N-th item is processing.
(N+1)-th item -> M-th block
N-th item -> (M+1)-th block
if block is fulled, N-th item need to be added in (M+1)-th block and this will occur miss ordering issue.
so when it need to be processed,
all pre-exist queuing items must be processed in order.