public String getStreamId() {
    return streamId;
  }
The following fields are serialized by the ExecutionPlanner when generating the configs for the output stream, and
deserialized once during startup in SamzaContainer. They don't need to be deserialized here on a per-task basis

Serdes are optional for intermediate streams and may be specified for job.default.system in configuration instead.
samza-core/src/main/java/org/apache/samza/operators/spec/OutputStreamImpl.java