code: @NullSafe
    public static <T> int indexOf(T[] array, T element) {
  
      for (int index = 0, length = nullSafeLength(array); index < length; index++) {
        if (equalsIgnoreNull(array[index], element)) {
          return index;
        }
      }
  
      return -1;
    }
docs: Null-safe method to find the index of the given {@code element} in the given {@code array}.
  
  @param <T> {@link Class} type of elements in the array.
  @param array array used to search for {@code element}.
  @param element {@link Object} element to search for in the given {@code array}.
  @return the index of the given {@code element} in the given {@code array} or return {@literal -1}
  if {@code element} could not be found.