public Set<SystemStream> getBootstrapStreams() {
    Set<SystemStream> bootstrapInputs = new HashSet<>();
    Set<SystemStream> allInputs = taskConfig.getAllInputStreams();
    for (SystemStream systemStream : allInputs) {
      if (streamConfig.getBootstrapEnabled(systemStream)) {
        bootstrapInputs.add(systemStream);
      }
    }
    return Collections.unmodifiableSet(bootstrapInputs);
  }
@return  the set of SystemStreams which were configured as bootstrap streams.
samza-core/src/main/java/org/apache/samza/config/DefaultChooserConfig.java