Avoid "Warning: Constant LARAVEL_START already defined" (#26)

* Avoid "Warning: Constant LARAVEL_START already defined"

* Update README.md

* Static doesn't work like that

* Update README.md

* Update README.md

* Update README.md

* Update README.md

Author: GrahamCampbell

README.md

@@ -24,11 +24,16 @@ APP_RUNTIME=Runtime\Laravel\Runtime
 
 use Illuminate\Contracts\Http\Kernel;
 
+define('LARAVEL_START', microtime(true));
+
 require_once dirname(__DIR__).'/vendor/autoload_runtime.php';
 
-return function () {
-    define('LARAVEL_START', microtime(true));
-    $app = require_once __DIR__ . '/../bootstrap/app.php';
+return function (): Kernel {
+    static $app;
+
+    if (null === $app) {
+        $app = require dirname(__DIR__).'/bootstrap/app.php';
+    }
 
     return $app->make(Kernel::class);
 };
@@ -41,13 +46,17 @@ return function () {
 
 use Illuminate\Contracts\Console\Kernel;
 
+define('LARAVEL_START', microtime(true));
+
 require_once __DIR__.'/vendor/autoload_runtime.php';
 
-return function () {
-    define('LARAVEL_START', microtime(true));
-    $app = require_once __DIR__.'/bootstrap/app.php';
+return function (): Kernel {
+    static $app;
+
+    if (null === $app) {
+        $app = require __DIR__.'/bootstrap/app.php';
+    }
 
     return $app->make(Kernel::class);
 };
-
 ```