public String getStreamId(String streamName) {
    return physcialToId.getOrDefault(streamName, streamName);
  }
Get the streamId for the specified streamName

@param streamName the physical identifier of a stream
@return the streamId identifier for the stream or the queried streamName if it is not found.
samza-azure/src/main/java/org/apache/samza/system/eventhub/EventHubConfig.java