Shuffles the collection in place, using the given generator as a source for randomness.
Swift Standard Library
The random number generator to use when shuffling the collection.
You use this method to randomize the elements of a collection when you are using a custom random number generator. For example, you can use the shuffle(using:) method to randomly reorder the elements of an array.
Complexity: O(n), where n is the length of the collection.