protected String getStreamSecretKey(String system, String stream) {
    return get(String.format(CONFIG_STREAM_SECRET_KEY, system, stream));
  }
Get the Kinesis secret key for the system stream
@param system name of the system
@param stream name of the stream
@return Kinesis secret key
samza-aws/src/main/java/org/apache/samza/system/kinesis/KinesisConfig.java