diff --git a/.travis.yml b/.travis.yml
index abfb6dc..caf91cb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,6 +4,12 @@ dist: trusty
 
 matrix:
   include:
+  - php: '5.5'
+    env: PHPUNIT_VERSION="4"
+  - php: '5.6'
+    env: PHPUNIT_VERSION="5"
+  - php: '7.0'
+    env: SWOOLE_VERSION="v4.3.6" PHPUNIT_VERSION="6"
   - php: '7.1'
     env: SWOOLE_VERSION="v4.3.6" PHPUNIT_VERSION="7"
   - php: '7.2'
diff --git a/README.md b/README.md
index 14ffd37..db67f53 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,8 @@ API 文档：[https://apidoc.gitee.com/yurunsoft/YurunHttp](https://apidoc.gitee
 
 > 每个小版本的更新日志请移步到 Release 查看
 
+v4.2.0 重构 Swoole 处理器，并发请求性能大幅提升 (PHP 版本依赖降为 >= 5.5)
+
 v4.1.0 实现智能识别场景，自动选择适合 Curl/Swoole 环境的处理器
 
 v4.0.0 新增支持 `Swoole` 并发批量请求 (PHP >= 7.1)
@@ -51,7 +53,7 @@ v1.0-1.3 初期版本迭代
 ```json
 {
     "require": {
-        "yurunsoft/yurun-http": "^4.1.0"
+        "yurunsoft/yurun-http": "^4.2.0"
     }
 }
 ```
diff --git a/composer.json b/composer.json
index 804d021..fd94a2b 100644
--- a/composer.json
+++ b/composer.json
@@ -2,9 +2,8 @@
     "name": "yurunsoft/yurun-http",
     "description": "YurunHttp 是开源的 PHP HTTP 类库，支持链式操作，简单易用。支持 Curl、Swoole，支持 Http、Http2、WebSocket！",
     "require": {
-        "php": ">=7.1.0",
-        "psr/http-message": "~1.0",
-        "yurunsoft/swoole-co-pool": "^1.1.0"
+        "php": ">=5.5.0",
+        "psr/http-message": "~1.0"
     },
     "require-dev": {
         "swoft/swoole-ide-helper": "~2.0",
diff --git a/src/YurunHttp.php b/src/YurunHttp.php
index 1c800bb..76f02f5 100644
--- a/src/YurunHttp.php
+++ b/src/YurunHttp.php
@@ -23,7 +23,7 @@ abstract class YurunHttp
     /**
      * 版本号
      */
-    const VERSION = '4.1';
+    const VERSION = '4.2';
 
     /**
      * 设置默认处理器类
diff --git a/src/YurunHttp/Attributes.php b/src/YurunHttp/Attributes.php
index eaa5f88..a871744 100644
--- a/src/YurunHttp/Attributes.php
+++ b/src/YurunHttp/Attributes.php
@@ -168,6 +168,11 @@ abstract class Attributes
      */
     const HTTP2_PIPELINE = 'http2_pipeline';
 
+    /**
+     * 重试计数
+     */
+    const PRIVATE_RETRY_COUNT = '__retryCount';
+
     /**
      * 重定向计数
      */
@@ -178,4 +183,24 @@ abstract class Attributes
      */
     const PRIVATE_WEBSOCKET = '__websocket';
 
+    /**
+     * Http2 流ID
+     */
+    const PRIVATE_HTTP2_STREAM_ID = '__http2StreamId';
+
+    /**
+     * 是否为 Http2
+     */
+    const PRIVATE_IS_HTTP2 = '__isHttp2';
+
+    /**
+     * 是否为 WebSocket
+     */
+    const PRIVATE_IS_WEBSOCKET = '__isWebSocket';
+
+    /**
+     * 连接对象
+     */
+    const PRIVATE_CONNECTION = '__connection';
+
 }
diff --git a/src/YurunHttp/Handler/Curl.php b/src/YurunHttp/Handler/Curl.php
index a6a2c84..b20fbe9 100644
--- a/src/YurunHttp/Handler/Curl.php
+++ b/src/YurunHttp/Handler/Curl.php
@@ -320,6 +320,11 @@ private function getResponse($handler, $curlResult, $isDownload, $receiveHeaders
         $headerSize = curl_getinfo($handler, CURLINFO_HEADER_SIZE);
         $headerContent = substr($curlResult, 0, $headerSize);
         $body = substr($curlResult, $headerSize);
+        // PHP 7.0.0开始substr()的 string 字符串长度与 start 相同时将返回一个空字符串。在之前的版本中，这种情况将返回 FALSE 。
+        if(false === $body)
+        {
+            $body = '';
+        }
 
         // body
         $result = new Response($body, curl_getinfo($handler, CURLINFO_HTTP_CODE));
diff --git a/src/YurunHttp/Handler/Swoole.php b/src/YurunHttp/Handler/Swoole.php
index ebbf592..b6cf184 100644
--- a/src/YurunHttp/Handler/Swoole.php
+++ b/src/YurunHttp/Handler/Swoole.php
@@ -12,7 +12,6 @@
 use Yurun\Util\YurunHttp\Exception\WebSocketException;
 use Yurun\Util\YurunHttp\Handler\Swoole\HttpConnectionManager;
 use Yurun\Util\YurunHttp\Handler\Swoole\Http2ConnectionManager;
-use function Yurun\Swoole\Coroutine\batch;
 
 class Swoole implements IHandler
 {
@@ -180,6 +179,22 @@ public function buildRequest($request, $connection, &$http2Request)
      * @return bool
      */
     public function send($request)
+    {
+        $deferRequest = $this->sendDefer($request);
+        if($request->getAttribute(Attributes::PRIVATE_IS_HTTP2) && $request->getAttribute(Attributes::HTTP2_NOT_RECV))
+        {
+            return true;
+        }
+        return !!$this->recvDefer($deferRequest);
+    }
+
+    /**
+     * 发送请求，但延迟接收
+     *
+     * @param \Yurun\Util\YurunHttp\Http\Request $request
+     * @return \Yurun\Util\YurunHttp\Http\Request
+     */
+    public function sendDefer($request)
     {
         if([] !== ($queryParams = $request->getQueryParams()))
         {
@@ -196,73 +211,86 @@ public function send($request)
             $connection = $this->httpConnectionManager->getConnection($uri->getHost(), Uri::getServerPort($uri), 'https' === $uri->getScheme() || 'wss' === $uri->getScheme());
             $connection->setDefer(true);
         }
-        $redirectCount = $request->getAttribute(Attributes::PRIVATE_REDIRECT_COUNT, 0);
-        $statusCode = 0;
         $isWebSocket = $request->getAttribute(Attributes::PRIVATE_WEBSOCKET);
-        $retry = $request->getAttribute(Attributes::RETRY, 0);
-        for($i = 0; $i <= $retry; ++$i)
+        // 构建
+        $this->buildRequest($request, $connection, $http2Request);
+        // 发送
+        $path = $uri->getPath();
+        if('' === $path)
         {
-            // 构建
-            $this->buildRequest($request, $connection, $http2Request);
-            // 发送
-            $path = $uri->getPath();
-            if('' === $path)
-            {
-                $path = '/';
-            }
-            $query = $uri->getQuery();
-            if('' !== $query)
+            $path = '/';
+        }
+        $query = $uri->getQuery();
+        if('' !== $query)
+        {
+            $path .= '?' . $query;
+        }
+        if($isWebSocket)
+        {
+            if($isHttp2)
             {
-                $path .= '?' . $query;
+                throw new \RuntimeException('Http2 swoole handler does not support websocket');
             }
-            if($isWebSocket)
+            if(!$connection->upgrade($path))
             {
-                if($isHttp2)
-                {
-                    throw new \RuntimeException('Http2 swoole handler does not support websocket');
-                }
-                if(!$connection->upgrade($path))
-                {
-                    throw new WebSocketException(sprintf('WebSocket connect faled, error: %s, errorCode: %s', swoole_strerror($connection->errCode), $connection->errCode), $connection->errCode);
-                }
+                throw new WebSocketException(sprintf('WebSocket connect faled, error: %s, errorCode: %s', swoole_strerror($connection->errCode), $connection->errCode), $connection->errCode);
             }
-            else if(null === ($saveFilePath = $request->getAttribute(Attributes::SAVE_FILE_PATH)))
+        }
+        else if(null === ($saveFilePath = $request->getAttribute(Attributes::SAVE_FILE_PATH)))
+        {
+            if($isHttp2)
             {
-                if($isHttp2)
-                {
-                    $result = $connection->send($http2Request);
-                }
-                else
-                {
-                    $connection->execute($path);
-                }
+                $result = $connection->send($http2Request);
+                $request = $request->withAttribute(Attributes::PRIVATE_HTTP2_STREAM_ID, $result);
             }
             else
             {
-                if($isHttp2)
-                {
-                    throw new \RuntimeException('Http2 swoole handler does not support download file');
-                }
-                $connection->download($path, $saveFilePath);
-            }
-            if($isHttp2 && $request->getAttribute(Attributes::HTTP2_NOT_RECV))
-            {
-                return $result;
+                $connection->execute($path);
             }
-            $this->getResponse($request, $connection, $isWebSocket, $isHttp2);
-            $statusCode = $this->result->getStatusCode();
-            // 状态码为5XX或者0才需要重试
-            if(!(0 === $statusCode || (5 === (int)($statusCode/100))))
+        }
+        else
+        {
+            if($isHttp2)
             {
-                break;
+                throw new \RuntimeException('Http2 swoole handler does not support download file');
             }
+            $connection->download($path, $saveFilePath);
+        }
+       
+        return $request->withAttribute(Attributes::PRIVATE_IS_HTTP2, $isHttp2)
+                       ->withAttribute(Attributes::PRIVATE_IS_WEBSOCKET, $isHttp2)
+                       ->withAttribute(Attributes::PRIVATE_CONNECTION, $connection);
+    }
+
+    /**
+     * 延迟接收
+     *
+     * @param \Yurun\Util\YurunHttp\Http\Request $request
+     * @return \Yurun\Util\YurunHttp\Http\Response
+     */
+    public function recvDefer($request)
+    {
+        /** @var \Swoole\Coroutine\Http\Client|\Swoole\Coroutine\Http2\Client $connection */
+        $connection = $request->getAttribute(Attributes::PRIVATE_CONNECTION);
+        $retryCount = $request->getAttribute(Attributes::PRIVATE_RETRY_COUNT, 0);
+        $redirectCount = $request->getAttribute(Attributes::PRIVATE_REDIRECT_COUNT, 0);
+        $isHttp2 = '2.0' === $request->getProtocolVersion();
+        $isWebSocket = $request->getAttribute(Attributes::PRIVATE_WEBSOCKET);
+        $this->getResponse($request, $connection, $isWebSocket, $isHttp2);
+        $statusCode = $this->result->getStatusCode();
+        // 状态码为5XX或者0才需要重试
+        if((0 === $statusCode || (5 === (int)($statusCode/100))) && $retryCount < $request->getAttribute(Attributes::RETRY, 0))
+        {
+            $request = $request->withAttribute(Attributes::RETRY, ++$retryCount);
+            $deferRequest = $this->sendDefer($request);
+            return $this->recvDefer($deferRequest);
         }
         if(!$isWebSocket && $statusCode >= 300 && $statusCode < 400 && $request->getAttribute(Attributes::FOLLOW_LOCATION, true))
         {
             if(++$redirectCount <= ($maxRedirects = $request->getAttribute(Attributes::MAX_REDIRECTS, 10)))
             {
                 // 自己实现重定向
-                $uri = $this->parseRedirectLocation($this->result->getHeaderLine('location'), $uri);
+                $uri = $this->parseRedirectLocation($this->result->getHeaderLine('location'), $request->getUri());
                 if(in_array($statusCode, [301, 302, 303]))
                 {
                     $method = 'GET';
@@ -276,11 +304,11 @@ public function send($request)
             else
             {
                 $this->result = $this->result->withErrno(-1)
-                                                ->withError(sprintf('Maximum (%s) redirects followed', $maxRedirects));
+                                             ->withError(sprintf('Maximum (%s) redirects followed', $maxRedirects));
                 return false;
             }
         }
-        return true;
+        return $this->result;
     }
 
     /**
@@ -556,17 +584,20 @@ public function getHttp2ConnectionManager()
      */
     public function coBatch($requests, $timeout = null)
     {
-        $callbacks = [];
-        foreach($requests as $k => $request)
+        $handlers = [];
+        $results = [];
+        foreach($requests as $i => &$request)
+        {
+            $results[$i] = null;
+            $handlers[$i] = $handler = new Swoole;
+            $request = $handler->sendDefer($request);
+        }
+        unset($request);
+        foreach($requests as $i => $request)
         {
-            $callbacks[$k] = function() use($request){
-                $swooleHandler = new Swoole;
-                $swooleHandler->send($request);
-                $response = $swooleHandler->recv();
-                return $response;
-            };
+            $results[$i] = $handlers[$i]->recvDefer($request);
         }
-        return batch($callbacks, $timeout ?? -1);
+        return $results;
     }
 
 }
\ No newline at end of file