code: public @CheckForNull StackTraceElement getElement(@Nonnegative int depth) {
          if (depth < 0) throw new ArrayIndexOutOfBoundsException(depth);
  
          return elements.length > depth
                  ? elements[depth]
                  : null
          ;
      }
docs: Get element of given stack depth.
  
  @return Stack element of null if not present.