For Kinesis, it seems to be, that AWS organizes its folders on S3 like: "prefix/2019/02/09/13/kinesis-stream-name-2019-02-09-10-02-32-db1db7a9-c484-40d1-b7ec-7651a55e4677"

The date in the path is UTC-time, the date in the file name is the UTC-time of the first received byte in the Kinesis stream for the specific file. This is the default behavior, so it would be nice to implement it in localstack.
stream = {
        'DeliveryStreamType': delivery_stream_type,
        'KinesisStreamSourceConfiguration': delivery_stream_type_configuration,
        'HasMoreDestinations': False,
        'VersionId': '1',
        'CreateTimestamp': time.time(),
        'DeliveryStreamARN': firehose_stream_arn(stream_name),
        'DeliveryStreamStatus': 'ACTIVE',
        'DeliveryStreamName': stream_name,
        'Destinations': [],
        'Tags': tags
    }
    DELIVERY_STREAMS[stream_name] = stream
    if elasticsearch_destination:
        update_destination(stream_name=stream_name,
                           destination_id=short_uid(),
                           elasticsearch_update=elasticsearch_destination)
    if s3_destination:
        update_destination(stream_name=stream_name, destination_id=short_uid(), s3_update=s3_destination)
    
    event_publisher.fire_event(event_publisher.EVENT_FIREHOSE_CREATE_STREAM,
        payload={'n': event_publisher.get_hash(stream_name)})
    if delivery_stream_type == 'KinesisStreamAsSource':
        kinesis_stream_name = delivery_stream_type_configuration.get('KinesisStreamARN').split('/')[1]
        kinesis_connector.listen_to_kinesis(
            stream_name=kinesis_stream_name, fh_d_stream=stream_name,
            listener_func=process_records, wait_until_started=True,
            ddb_lease_table_suffix='-firehose', region_name=region_name)
    return stream
def delete_stream(stream_name):