public static String getNameFromSystemStream(SystemStream systemStream) {
    return systemStream.getSystem() + "." + systemStream.getStream();
  }
Returns the period separated system stream name for the provided {@code systemStream}. For
example, SystemStream("kafka", "topic") would return "kafka.topic".

@param systemStream the {@link SystemStream} to get the name for
@return the system stream name
samza-core/src/main/java/org/apache/samza/util/StreamUtil.java