enum.c:228
static VALUE
enum_partition(obj)
    VALUE obj;
{
    VALUE ary[2];

    ary[0] = rb_ary_new();
    ary[1] = rb_ary_new();
    rb_iterate(rb_each, obj, partition_i, (VALUE)ary);

    return rb_assoc_new(ary[0], ary[1]);
}
