How to access $_GET variables in plugins

[ttodua]

How to access $_GET variables in plugins, for example this doesnt work:

$dispatcher->addListener(Event\Radio\GenerateRawNowPlaying::class, function(Event\Radio\GenerateRawNowPlaying $event) {
    ...
    exit ( print_r($_REQUEST, true) );   //even `$_COOKIE` (or most of `$_SERVER`) variables are empty here, while outside they are working
    ...
	
 }, -1);

outputs empty Array() on player page ( example.com/public/my_station?param=abc ).
I want to get that param=abc $_GET variables.

___ UPDATE __
I've even tried to set $GLOBALS['MY_GET'] = $_GET['param']; or define('bla', $_GET['param']) in the top of plugin, and then use the globals inside events, neither it worked.

[ttodua]

As it was decided not to answer personally to me questions, I'm closing the issue.