code: function isRequired(target, reference, property) {
      // get the class constructor
      const constr = target.constructor;
      logger_1.log(`${constr.name}: checking if ${property} is required...`, "silly");
      // retrieve the current metadata
      const metadata = Reflect.getMetadata(METADATA_required, constr) || {};
      if (metadata.hasOwnProperty(property)) {
          const ret = metadata[property];
          if (typeof ret === "boolean")
              return ret;
          return ret(target, reference);
      }
      return false;
  }
docs: Checks if a property is required to be present in a serialized CoAP object
  @param property - property name to lookup