src/it/unimi/dsi/fastutil/Arrays.java
protected static void swap(final Swapper swapper, int a, int b, final int n) {
		for (int i = 0; i < n; i++, a++, b++) swapper.swap(a, b);
	}
protected static void swap(final Swapper swapper, int a, int b, final int n) {
		for (int i = 0; i < n; i++, a++, b++) swapper.swap(a, b);
	}
Swaps two sequences of elements using a provided swapper.

@param swapper the swapper.
@param a a position in {@code x}.
@param b another position in {@code x}.
@param n the number of elements to exchange starting at {@code a} and {@code b}.