idea - prefetch in SSD

把read request所要的data從快gc的channel先prefetch出來…

好處:  reduce latency

方法:1  prefetch 時 prefer 快 GC的 channel
                  → 怎麼判斷 "快GC"       (elem utilization, pended wt req)
                  →要prefetch 什麼 data ? (from history, seq ratio)