in src/main/scala/com/gu/contentapi/firehose/kinesis/SingleEventProcessor.scala [88:92]
def shutdownRequested(shutdownRequestedInput: ShutdownRequestedInput): Unit = {
shutdownRequestedInput.checkpointer().checkpoint()
logger.info(s"Shutdown event processor for shard $shardId because shutdown was requested")
shutdown(ShutdownReason.REQUESTED)
}