save index of head into pool->queue[tail] at time of acquire
save index of head into pool->queue[tail] at time of acquire

DenverM80/ds3_c_sdk,DenverM80/ds3_c_sdk,DenverM80/ds3_c_sdk,SpectraLogic/ds3_c_sdk,DenverM80/ds3_c_sdk,SpectraLogic/ds3_c_sdk,SpectraLogic/ds3_c_sdk,SpectraLogic/ds3_c_sdk