@Override
  public TypeInformation<T> getProducedType() {
    return typeInformation;
  }
generate mixed-format watermark. This is only for lookup join mixed-format table, and
mixed-format table is used as build table, i.e. right table.
amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common/src/main/java/org/apache/amoro/flink/read/MixedFormatSource.java