Function first

src/rpp/rpp/operators/first.hpp:91–94

* @brief Emit only the first item. * * @marble first { source observable : +--1--2--3--| operator "first" : +--1| } * * @details Actually this operator is `take(1)` with exception during `on_completed` if no any emision happens. So, it just forwards first obtained emission and emits on_completed immediately * @throws rpp::ut

     * @see https://reactivex.io/documentation/operators/first.html
     */
    inline auto first()
    {
        return details::first_t{};
    }
} // namespace rpp::operators