message: Improve recv slow test.
diff: @@ -6,28 +6,27 @@ swoole_http_client_coro: recv_all data from slow server
  <?php
  require __DIR__ . '/../include/bootstrap.php';
  -$content = str_repeat(openssl_random_pseudo_bytes(1024), 1024 * (IS_IN_TRAVIS ? 1 : 5));
  -file_put_contents('/tmp/test.jpg', $content);
  -
  $pm = new ProcessManager;
  $pm->parentFunc = function ($pid) use ($pm) {
  + for ($c = MAX_CONCURRENCY_LOW; $c--;) {
  go(function () use ($pm) {
  $cli = new Swoole\Coroutine\Http\Client('127.0.0.1', $pm->getFreePort());
  $cli->set(['timeout' => 1]);
  $s = microtime(true);
  $ret = $cli->get('/');
  $s = microtime(true) - $s;
  - phpt_var_dump($s, $cli);
  + phpt_var_dump($s);
  if (assert(!$ret)) {
  assert($cli->errCode === SOCKET_ETIMEDOUT);
  assert($cli->statusCode === SWOOLE_HTTP_CLIENT_ESTATUS_REQUEST_TIMEOUT);
  assert(time_approximate(1, $s));
  }
  $cli->close();
  - @unlink('/tmp/test.jpg');
  + });
  + }
  + Swoole\Event::wait();
  $pm->kill();
  echo "DONE\n";
  - });
  };
  $pm->childFunc = function () use ($pm) {
  @@ -52,7 +51,7 @@ $pm->childFunc = function () use ($pm) {
  for ($n = 0; $n < strlen($data); $n++) {
  var_dump_return("send {$n}\n");
  $client->send($data{$n});
  - usleep(10 * 1000);
  + usleep(mt_rand(10, 800) * 1000);
  }
  });
  }
  