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# Type of request: This is a ...
[x] bug report
[ ] feature request

# Detailed description
Currently when using [software.amazon.awssdk:kinesis:2.15.27](https://search.maven.org/artifact/software.amazon.awssdk/kinesis/2.15.27/jar) and attempting to use [getRecords](https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/kinesis/KinesisAsyncClient.html#getRecords-java.util.function.Consumer-) we end up getting a general aws client exception `software.amazon.awssdk.core.exception.SdkClientException: Unable to parse date : 1.605283809962E9`. This doesn't happen when using a live kinesis stream.

## Expected behavior
Should be able to get a response from localstack with the correct data.

## Actual behavior
An exception is thrown from inside aws sdk v2 with the message `software.amazon.awssdk.core.exception.SdkClientException: Unable to parse date : 1.605283809962E9`.

# Steps to reproduce
## Command used to start LocalStack
`docker run -d -p 4566:4566 -e "SERVICES=kinesis" localstack/localstack:0.12.2`

## Client code (AWS SDK code snippet, or sequence of "awslocal" commands)
https://github.com/lukecollier/localstack-jvm-aws-sdk-v2



┆Issue is synchronized with this [Jira Task](https://localstack.atlassian.net/browse/LOC-53) by [Unito](https://www.unito.io/learn-more)

global STREAM_CONSUMERS
        data = self.decode_content(data or '{}')
        action = headers.get('X-Amz-Target', '').split('.')[-1]
        if action == 'RegisterStreamConsumer':
            consumer = clone(data)
            consumer['ConsumerStatus'] = 'ACTIVE'
            consumer['ConsumerARN'] = '%s/consumer/%s' % (data['StreamARN'], data['ConsumerName'])
            consumer['ConsumerCreationTimestamp'] = float(now_utc())
            consumer = json_safe(consumer)
            STREAM_CONSUMERS.append(consumer)
            return {'Consumer': consumer}
        elif action == 'DeregisterStreamConsumer':
            def consumer_matches(c):