docs: public String getMarshallingType() {
          if (isList()) {
              return "LIST";
          } else if (isMap()) {
              return "MAP";
          } else if (isJsonValue()) {
              return "JSON_VALUE";
          } else if (!isSimple()) {
              return "STRUCTURED";
          } else {
              return TypeUtils.getMarshallingType(variable.getSimpleType());
          }
      }