fastcache doesn't store value with length of exactly 512k

[AlexBlack772]

I've faced with an issue that fastcache doesn't store value with length of exactly 512k

func main() {
	cache := fastcache.New(1024)

	var key, val []byte

	key = []byte("k")
	val = make([]byte, 512000)

	cache.SetBig(key, val)
	val = cache.GetBig(nil, key)

	if val == nil {
		fmt.Println("Value is missing")
	} else {
		fmt.Println("Value is OK")
		fmt.Println(len(val))
	}
}

The code prints "Value is missing", but if I create val as make([]byte, 512000+1) then I can set and get value.