generateMulti function
Convert an array of multiple strings into a Redis slot hash. Returns -1 if one of the keys is not for the same slot as the others.
Implementation
int generateMulti(List<String> keys) {
var i = 1;
final len = keys.length;
final base = generate(keys[0]);
while (i < len) {
if (generate(keys[i++]) != base) return -1;
}
return base;
}