Can it be possible to track all the set variable by `$this->set('variable_name', 'some_value')`
in the controller's method itself.
Actually i have a method that call several other method and each sub method set the value to view. Now I am unable to track if the same key set twice in the main method or not.

example

```
    function beforeFilter()
{
    $this->set('key1', 'viable value');
}

function reqMethod()
{
    $this->extendMethod1();
    $this->extendMethod2();
    $this->extendMethod3();
    $this->extendMethod4();
    $this->extendMethod5();
    $this->extendMethod6();
            // Want to track all set variable (key) here.
}

private function extendMethod1()
{
    $this->set('key1', 'unknow value');
}

```

Here it may possible that key1 (by mistake) can be set to another method.
Any help really be appreciated.