fix handler function response

README.md

@@ -84,7 +84,8 @@ $server->start(
         string $content,
         string $request,
         string $connect
-    ) {
+    ): ?string
+    {
         printf(
             'connection: %s request: %s',
             $connect,
@@ -97,6 +98,8 @@ $server->start(
                 $content
             );
         }
+
+        return 'thank you!';
     }
 );
 ```

src/Server.php

@@ -185,10 +185,6 @@ class Server
                 false
             );
 
-            fclose(
-                $incoming
-            );
-
             if ($handler)
             {
                 $response = call_user_func(
@@ -198,8 +194,20 @@ class Server
                     $request,
                     $connect
                 );
+
+                if ($response)
+                {
+                    fwrite(
+                        $incoming,
+                        $response
+                    );
+                }
             }
 
+            fclose(
+                $incoming
+            );
+
         } while ($this->_live);
     }