In [this PR](https://github.com/localstack/localstack/pull/1200/files) we introduced a new way of starting S3 in a separate process.

In the meantime, the service startup has been significantly reworked, and it seems that we can integrate the S3 starter into the [`multiserver.py`](https://github.com/localstack/localstack/blob/master/localstack/utils/server/multiserver.py) based loading approach that loads multiple APIs in a single process, for performance reasons. We should look into that.
resources = client.get_resources(restApiId=new_id, limit=500)['items']
            
            assert len(resource.resources) == 1
            resource.resources = {}
            for res in resources:
                res_path_part = res.get('pathPart') or res.get('path')
                child = resource.add_child(res_path_part, res.get('parentId'))
                resource.resources.pop(child.id)
                child.id = res['id']
                child.api_id = new_id
                resource.resources[child.id] = child
            resource.id = new_id
        elif isinstance(resource, apigw_models.Resource):
            api_id = props['RestApiId']
            backend.apis[api_id].resources.pop(resource.id, None)
            backend.apis[api_id].resources[new_id] = resource
            resource.id = new_id
        elif isinstance(resource, apigw_models.Deployment):
            api_id = props['RestApiId']
            backend.apis[api_id].deployments.pop(resource['id'], None)
            backend.apis[api_id].deployments[new_id] = resource
            resource['id'] = new_id
        else:
            LOG.warning('Unexpected resource type when updating ID: %s' % type(resource))
    parse_and_create_resource_orig = parsing.parse_and_create_resource
    parsing.parse_and_create_resource = parse_and_create_resource
    parse_and_update_resource_orig = parsing.parse_and_update_resource
    parsing.parse_and_update_resource = parse_and_update_resource
    
    def parse_output(output_logical_id, output_json, resources_map):