diff --git a/examples/coroutine.php b/examples/coroutine.php
new file mode 100755
index 0000000..e38f4a1
--- /dev/null
+++ b/examples/coroutine.php
@@ -0,0 +1,46 @@
+<?php
+
+$host = '127.0.0.1';
+$port = 5188;
+$data = '{"controller":"site","methor":"test","params":{"id":1}}';
+
+
+$length = strlen($data);
+$pack = pack('CNNNa*', 1, time(), 0, $length, $data);
+
+$ret = Swoole\Coroutine::create(function()use($host, $port, $pack) {
+    $client = new Swoole\Coroutine\Client(SWOOLE_SOCK_TCP);
+    $client->set(array(
+        'open_length_check' => true,
+        'package_max_length' => 81920,
+        'package_length_type' => 'N',
+        'package_length_offset' => 9,
+        'package_body_offset' => 13,
+        'connect_timeout' => 1.0,
+        'write_timeout' => 60.0,
+        'read_timeout' => 60.0
+    ));
+
+    if (!$client->connect($host, $port)) {
+        echo "connect failed.\n";
+        return false;
+    }
+
+
+    @$client->send($pack);
+    $pack = @$client->recv();
+    if ($pack === false) {
+        echo $client->errCode . "\n";
+        return false;
+    } else if (empty($pack)) {
+        echo "close by peer.\n";
+        return false;
+    }
+
+    $ret = unpack('Ctype/Ntime/Nserid/Nlength/a*data', $pack);
+    $client->close();
+    return $ret['data'];
+});
+
+
+print_r($ret);
\ No newline at end of file
diff --git a/src/Pack.php b/src/Pack.php
index 10957cc..0b6f156 100644
--- a/src/Pack.php
+++ b/src/Pack.php
@@ -132,8 +132,8 @@ class Pack {
      */
     public function unpack(string $pack) {
         try {
-            $ret = unpack($this->makeFormat(true), $pack);
-            if ($ret['type'] === self::DATA_TYPE_SAMPLE_DATA && $ret['length'] == strlen($ret['data']) && (int) $ret['length'] <= self::$packageMaxLength) {
+            $ret = @unpack($this->makeFormat(true), $pack);
+            if (is_array($ret) && $ret['type'] === self::DATA_TYPE_SAMPLE_DATA && $ret['length'] == strlen($ret['data']) && (int) $ret['length'] <= self::$packageMaxLength) {
                 return $ret;
             }
         } catch (\Exception $e) {