Function invoke_lambda_async 

pub fn invoke_lambda_async(
    container_runtime: &Option<Arc<ContainerRuntime>>,
    lambda_state: &Option<SharedLambdaState>,
    function_arn: &str,
    payload: &str,
)

Spawn a background task to invoke a Lambda function via ContainerRuntime. This is fire-and-forget: EventBridge delivery is asynchronous.