key=0 val=1
key=1 val=2
key=2 val=3
key=3 val=4
key=a val=7
array(5) {
  [0]=>
  int(2)
  [1]=>
  int(0)
  [2]=>
  int(3)
  [3]=>
  int(5)
  ["a"]=>
  &int(8)
}