rusoto_kines: calling next on EventStream<rusoto_kinesis::SubscribeToShardEventStreamItem> fails after the stream is re-sharded

[RichardChester]

After reducing the number of shards I keep getting a parse error when calling next on the event stream. This error appears to be internal to rusoto as it is trying to parse the payload being sent into an SubscribeToShardEvent however the payload it's receiving is a ChildShard(which is optionally present in a SubscribeToShardEvent).

[RichardChester]

I think that a new struct needs adding to the SubscribeToShardEventStreamItem as when you re-shard and it reaches the end of the stream the payload sent from kinesis doesn't match any of the options. for it to work you would need to add a SubscribeToShardEventStreamItem::ChildShard and you know if you receive it when calling next on the event stream that there has been a re-shard and you may need to connect to the new shard