message: Update exit example.
diff: <?php
  +function route()
  +{
  + controller();
  +}
  +
  +function controller()
  +{
  + your_code();
  +}
  +
  +function your_code()
  +{
  + co::sleep(.001);
  + exit(1);
  +}
  +
  go(function () {
  - $a = "hello";
  - $b = "world";
  - $str = $a.str_repeat(' ', 1).$b."\n";
  - echo $str;
  - exit($str);
  + try {
  + route();
  + } catch (\Swoole\ExitException $e) {
  + assert($e->getStatus() === 1);
  + assert($e->getFlags() === SWOOLE_EXIT_IN_COROUTINE);
  + return;
  + }
  });
  \ No newline at end of file
  