producer putting item-0 at 0
producer sleeping at 0
consumer waiting for 0 at 0
consumer got item-0 at 0
consumer waiting for 1 at 0
producer putting item-1 at 2
producer sleeping at 2
consumer got item-1 at 2
consumer waiting for 2 at 2
producer putting item-2 at 4
producer sleeping at 4
consumer got item-2 at 4
