src/Gateways/GatewayCallback.php
public function onCallbackFail($order, $data = null)
    {
        $this->statusCode   = 'failed';
        $this->detail       = 'failed callback';
        $this->didCallback  = true;
    }
public function onCallbackFail($order, $data = null)
    {
        $this->statusCode   = 'failed';
        $this->detail       = 'failed callback';
        $this->didCallback  = true;
    }
Called on callback.

@param Order $order Order.
@param mixed $data  Request input from callback.

@return bool