Description:
------------
Add current array index as second argument to the callback of array_map

Test script:
---------------
<?php

$array = array(
    'foo' => 23,
    'bar' => 42
);

$result = array_map(function() {
    return implode(':', func_get_args());
}, $array);

var_dump($result);




Expected result:
----------------
array(2) {
  ["foo"]=>
  string(2) "23:foo"
  ["bar"]=>
  string(2) "42:foo"
}


Actual result:
--------------
array(2) {
  ["foo"]=>
  string(2) "23"
  ["bar"]=>
  string(2) "42"
}