public static int checkPositionIndex(int index, int size) {
		return checkPositionIndex(index, size, "index");
	}
Ensures that {@code index} specifies a valid <i>position</i> in an array, list or string of size {@code size}. A
position index may range from zero to {@code size}, inclusive.

@param index a user-supplied index identifying a position in an array, list or string
@param size  the size of that array, list or string
@return the value of {@code index}
ngrinder-core/src/main/java/org/ngrinder/common/util/Preconditions.java