@Override
  public <StreamMessageType> GenericInputDescriptor<StreamMessageType> getInputDescriptor(
      String streamId, Serde<StreamMessageType> serde) {
    return new GenericInputDescriptor<>(streamId, this, serde);
  }
Constructs a {@link GenericSystemDescriptor} instance with no system level serde.
Serdes must be provided explicitly at stream level when getting input or output descriptors.

@param systemName name of this system
@param factoryClassName name of the SystemFactory class for this system
samza-api/src/main/java/org/apache/samza/system/descriptors/GenericSystemDescriptor.java