@SuppressWarnings("OptionalGetWithoutIsPresent") @Override public StructField getStructFieldRef(String fieldName) {
      return this.getAllStructFieldRefs()
          .stream()
          .filter(ref -> ref.getFieldName().equals(fieldName))
          .findFirst()
          .get();
    }
Look up a field.

@param fieldName fieldName to be looked up.
kafka-handler/src/java/org/apache/hadoop/hive/kafka/KafkaSerDe.java