Client does not handle streams with more than 100 shards

[jhecking]

The AWS.DynamoDBStreams.describeStream() function returns max. 100 shards. If the stream consists of more shards than that, the response contains a LastEvaluatedShardId value, which can be passed in a subsequent describeStream() call using the ExclusiveStartShardId parameter, to fetch the remaining shards.

Because the client does not fetch all the shards, it will miss records on very active streams.

[jhecking]

Looks like someone else already ran into the same issue as well and addressed it in this commit: zoom-us@aee2f2c. Possible to pull this change and release it in the "official" dynamodb-stream package on npmjs.com?