refactor(headercredential): refactor applyToRequest method

- Change parent class from KeyValueCredential to NullCredential
- Add headers property to store headers
- Modify constructor to accept an array of headers
- Implement applyToRequest method using array_reduce_with_keys function to apply headers to the request

src/Foundation/Credentials/HeaderCredential.php

@@ -12,10 +12,26 @@
 
 namespace Guanguans\Notify\Foundation\Credentials;
 
-class HeaderCredential extends KeyValueCredential
+use Psr\Http\Message\RequestInterface;
+
+class HeaderCredential extends NullCredential
 {
-    public function __construct(string $value, string $key = 'Authorization')
+    private array $headers;
+
+    public function __construct(array $headers)
+    {
+        $this->headers = $headers;
+    }
+
+    public function applyToRequest(RequestInterface $request): RequestInterface
     {
-        parent::__construct($key, $value);
+        return array_reduce_with_keys(
+            $this->headers,
+            static fn (RequestInterface $request, $value, string $header): RequestInterface => $request->withHeader(
+                $header,
+                $value
+            ),
+            $request
+        );
     }
 }

src/Foundation/Support/helpers.php

@@ -125,3 +125,19 @@ public function __call($method, $parameters)
         return $value;
     }
 }
+
+if (! function_exists('array_reduce_with_keys')) {
+    /**
+     * @param null|mixed $carry
+     *
+     * @return null|mixed
+     */
+    function array_reduce_with_keys(array $array, callable $callback, $carry = null)
+    {
+        foreach ($array as $key => $value) {
+            $carry = $callback($carry, $value, $key);
+        }
+
+        return $carry;
+    }
+}