instance (id) with dynamic elements;
protected id initWithEnumerator Enumerator e;
_builtin_.Any at int index;
byte at int index;
char at int index;
int at int index;
long at int index;
float at int index;
double at int index;
int elementByteSize;
int hash;
(pointer, int) pointerToElements (int, int) (start, len);
class (State) mutableCopyClass;
MutableIntArray
class.