class TestHandler implements TaskHandlerInterface, RetryTaskHandlerInterface
{

    public function getMaximumAttempts()
    {
        return 3;
    }

    public function handle($workload)
    {
        try {
            $this->doSomething();
        } catch (SpecificException $exception) {
            throw new FailedException($exception);
        }
        
        // other exceptions will be propagated to the runner
        // the runner will retry the execution until the max-attempts are reached
    }
}