Attempted to load class "EventDispatcher" from namespace "Unleash\Client\Helper".
  Did you forget a "use" statement for e.g. "Symfony\Component\EventDispatcher\EventDispatcher" or "JMS\Serializer\EventDispatche
  r\EventDispatcher"?

app.WARNING: Failed to generate ConfigBuilder for extension Unleash\Client\Bundle\DependencyInjection\UnleashSymfonyClientExtension: Impossible to call set() on a frozen ParameterBag. {"exception":"[object] (Symfony\\Component\\DependencyInjection\\Exception\\LogicException(code: 0): Impossible to call set() on a frozen ParameterBag. at /home/somebody/projects/my-app/vendor/symfony/dependency-injection/ParameterBag/FrozenParameterBag.php:58)","extensionClass":"Unleash\\Client\\Bundle\\DependencyInjection\\UnleashSymfonyClientExtension"} []
11:03:31 WARNING   [app] Failed to generate ConfigBuilder for extension Unleash\Client\Bundle\DependencyInjection\UnleashSymfonyClientExtension: Impossible to call set() on a frozen ParameterBag. ["exception" => Symfony\Component\DependencyInjection\Exception\LogicException^ { …},"extensionClass" => "Unleash\Client\Bundle\DependencyInjection\UnleashSymfonyClientExtension"]
[2023-11-28T11:03:31.795406+00:00] php.CRITICAL: Uncaught Error: Class "Unleash\Client\Helper\EventDispatcher" not found {"exception":"[object] (Error(code: 0): Class \"Unleash\\Client\\Helper\\EventDispatcher\" not found at /home/somebody/projects/my-app/var/cache/dev/ContainerVjTV1Xw/My_App_KernelDevDebugContainer.php:1841)"} []
11:03:31 CRITICAL  [php] Uncaught Error: Class "Unleash\Client\Helper\EventDispatcher" not found ["exception" => Error { …}]

In My_App_KernelDevDebugContainer.php line 1841:

  Attempted to load class "EventDispatcher" from namespace "Unleash\Client\Helper".
  Did you forget a "use" statement for e.g. "Symfony\Component\EventDispatcher\EventDispatcher" or "JMS\Serializer\EventDispatche
  r\EventDispatcher"?