function during(propertyName, begin, end) {
  return new During(propertyName, begin, end);
}
Create a `<During>` temporal operator.

@param {!string} propertyName Name of the context property to compare.
@param {!string} begin The begin date in ISO-8601 format.
@param {!string} end The end date in ISO-8601 format.
@return {!During} `<During>` operator.
@api