code: public FieldValue get(String name) {
      if (schema == null) {
        throw new UnsupportedOperationException(
            "Retrieving field value by name is not supported when there is no fields schema provided");
      }
      return get(schema.getIndex(name));
    }
docs: Gets field value by index.
  
  @param name field name (defined in schema)
  @throws IllegalArgumentException if schema is not provided or if {@code name} was not found in
  the schema