diff --git a/.php_cs b/.php_cs
index 8cbe9c4..d438a45 100644
--- a/.php_cs
+++ b/.php_cs
@@ -1,28 +1,49 @@
 <?php
-$header = <<<EOF
-This file is part of the overtrue/http.
-
-(c) overtrue <i@overtrue.me>
-
-This source file is subject to the MIT license that is bundled
-with this source code in the file LICENSE.
-EOF;
 
 return PhpCsFixer\Config::create()
-    ->setRiskyAllowed(true)
-    ->setRules(array(
-        '@Symfony' => true,
-        'header_comment' => array('header' => $header),
-        'array_syntax' => array('syntax' => 'short'),
-        'ordered_imports' => true,
-        'no_useless_else' => true,
-        'no_useless_return' => true,
-        'php_unit_construct' => true,
-        'php_unit_strict' => true,
-    ))
+    ->setRules([
+        '@PSR2' => true,
+        'binary_operator_spaces' => true,
+        'blank_line_after_opening_tag' => true,
+        'compact_nullable_typehint' => true,
+        'declare_equal_normalize' => true,
+        'lowercase_cast' => true,
+        'lowercase_static_reference' => true,
+        'new_with_braces' => true,
+        'no_unused_imports' => true,
+        'no_blank_lines_after_class_opening' => true,
+        'no_leading_import_slash' => true,
+        'no_whitespace_in_blank_line' => true,
+        'ordered_class_elements' => [
+            'order' => [
+                'use_trait',
+            ],
+        ],
+        'ordered_imports' => [
+            'imports_order' => [
+                'class',
+                'function',
+                'const',
+            ],
+            'sort_algorithm' => 'none',
+        ],
+        'return_type_declaration' => true,
+        'short_scalar_cast' => true,
+        'single_blank_line_before_namespace' => true,
+        'single_trait_insert_per_statement' => true,
+        'ternary_operator_spaces' => true,
+        'unary_operator_spaces' => true,
+        'visibility_required' => [
+            'elements' => [
+                'const',
+                'method',
+                'property',
+            ],
+        ],
+    ])
     ->setFinder(
         PhpCsFixer\Finder::create()
             ->exclude('vendor')
-            ->in(__DIR__)
+            ->in([__DIR__.'/src/', __DIR__.'/tests/'])
     )
-;
\ No newline at end of file
+;
diff --git a/composer.json b/composer.json
index 87d28b9..3805c61 100644
--- a/composer.json
+++ b/composer.json
@@ -11,9 +11,11 @@
         "ext-libxml": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": "^6.5 || ^8.0",
+        "phpunit/phpunit": "^6.5 || ^8.5",
         "mockery/mockery": "^1.0",
-        "overtrue/phplint": "^1.1 || ^2.0"
+        "overtrue/phplint": "^1.1 || ^2.0",
+        "brainmaestro/composer-git-hooks": "^2.7",
+        "friendsofphp/php-cs-fixer": "^2.15"
     },
     "autoload": {
         "psr-4": {
@@ -26,5 +28,24 @@
             "name": "overtrue",
             "email": "anzhengchao@gmail.com"
         }
-    ]
+    ],
+    "scripts": {
+        "post-update-cmd": [
+            "cghooks update"
+        ],
+        "post-merge": "composer install",
+        "post-install-cmd": [
+            "cghooks add --ignore-lock",
+            "cghooks update"
+        ],
+        "cghooks": "vendor/bin/cghooks",
+        "check-style": "php-cs-fixer fix --using-cache=no --diff --config=.php_cs --dry-run --ansi",
+        "fix-style": "php-cs-fixer fix --using-cache=no --config=.php_cs --ansi",
+        "test": "vendor/bin/phpunit --colors=always"
+    },
+    "scripts-descriptions": {
+        "test": "Run all tests.",
+        "check-style": "Run style checks (only dry run - no fixing!).",
+        "fix-style": "Run style checks and fix violations."
+    }
 }
diff --git a/src/Client.php b/src/Client.php
index c28e183..fa6538e 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -264,14 +264,17 @@ public function uploadAsync(string $uri, array $files = [], array $form = [], ar
      * @param array  $options
      * @param bool   $async
      *
-     * @return \Psr\Http\Message\ResponseInterface|\Overtrue\Http\Support\Collection|array|object|string
+     * @return \Psr\Http\Message\ResponseInterface|\GuzzleHttp\Promise\PromiseInterface|\Overtrue\Http\Support\Collection|array|object|string
      */
     public function request(string $uri, string $method = 'GET', array $options = [], bool $async = false)
     {
-        return $this->castResponseToType(
-            $this->requestRaw($uri, $method, $options, $async),
-            $this->config->getOption('response_type')
-        );
+        $result = $this->requestRaw($uri, $method, $options, $async);
+
+        $transformer = function ($response) {
+            return $this->castResponseToType($response, $this->config->getOption('response_type'));
+        };
+
+        return $async ? $result->then($transformer) : $transformer($result);
     }
 
     /**
@@ -280,7 +283,7 @@ public function request(string $uri, string $method = 'GET', array $options = []
      * @param array  $options
      * @param bool   $async
      *
-     * @return array|object|\Overtrue\Http\Support\Collection|\Psr\Http\Message\ResponseInterface|string
+     * @return \Psr\Http\Message\ResponseInterface|\GuzzleHttp\Promise\PromiseInterface|\Overtrue\Http\Support\Collection|array|object|string
      */
     public function requestRaw(string $uri, string $method = 'GET', array $options = [], bool $async = false)
     {
diff --git a/src/Config.php b/src/Config.php
index 30f6003..cbd40a2 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -24,10 +24,10 @@ class Config
      * @var array
      */
     protected $options = [
-        'base_uri'        => null,
-        'timeout'         => 3000,
+        'base_uri' => null,
+        'timeout' => 3000,
         'connect_timeout' => 3000,
-        'proxy'           => [],
+        'proxy' => [],
     ];
 
     /**
diff --git a/src/Traits/HasHttpRequests.php b/src/Traits/HasHttpRequests.php
index 015c8c9..6b28c08 100644
--- a/src/Traits/HasHttpRequests.php
+++ b/src/Traits/HasHttpRequests.php
@@ -13,7 +13,6 @@
 
 use GuzzleHttp\Client;
 use GuzzleHttp\ClientInterface;
-use Psr\Http\Message\ResponseInterface;
 
 /**
  * Trait HasHttpRequests.