public function listen($channel, $expr, callable $handler)
    {
        $this->adapter->subscribe($channel, function ($message) use ($expr, $handler) {
            $this->handleSubscribeCallback($message, $expr, $handler);
        });
    }
public function listen($channel, $expr, callable $handler)
    {
        $this->adapter->subscribe($channel, function ($message) use ($expr, $handler) {
            $this->handleSubscribeCallback($message, $expr, $handler);
        });
    }
public function listen ( $ channel , $ expr , callable $ handler ) { $ this -> adapter -> subscribe ( $ channel , function ( $ message ) use ( $ expr , $ handler ) { $ this -> handleSubscribeCallback ( $ message , $ expr , $ handler ) ; } ) ; }
Listen for an event.

@param string $channel
@param string $expr
@param callable $handler
Listen for an event .