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

@param index a user-supplied index identifying an element of an array, list or string
@param size the size of that array, list or string
@return the value of {@code index}
@throws IndexOutOfBoundsException if {@code index} is negative or is not less than {@code size}
@throws IllegalArgumentException if {@code size} is negative
fbcore/src/main/java/com/facebook/common/internal/Preconditions.java