go run cmd/main.go -sampling-bound=1000000 -bytes-size=4 -iterator-size=4
    -sampling-bound: should be greater than 131072 (8*(4**7))
    -bytes-size: should be greater than 4
    -iterator-size: iterator's data array size, should be greater than 0 and less than 100

KV is struct with []byte as Key and Iterator as Value;
    Key is parsed from randomly generated int32 with BigEndian
    Iterator is very simply constructed, probably very slow.