code: function getSourceStreamName(record, context) {
    if (isDynamoDBStreamType(context)) {
      const [tableName, streamTimestamp] = streamEvents.getDynamoDBEventSourceTableNameAndStreamTimestamp(record);
      return tableName && streamTimestamp ? `${tableName}/${streamTimestamp}` : '';
    } else {
      return streamEvents.getKinesisEventSourceStreamName(record);
    }
  }
docs: Extracts the source stream names from the given Kinesis or DynamoDB stream event record.
  For Kinesis: Extract the stream name from the record's eventSourceARN
  For DynamoDB: Extract the table name and stream timestamp from the record's eventSourceARN and join them with a '/'
  @param {AnyStreamEventRecord} record - the record from which to extract
  @param {StreamProcessing} context - the context from which to fetch the function
  @return {string} the source stream name