Method start

include/exec/sequence/merge_each.hpp:1198–1212

      {}

      void start() & noexcept
      {
        this->__nested_stop_.register_token(this->__rcvr_);
        if (this->__nested_stop_.stop_requested())
        {
          // Stop has already been requested. Don't bother starting
          // the child operations.
          STDEXEC::set_stopped(static_cast<_Receiver&&>(this->__rcvr_));
        }
        else
        {
          this->sequence_started();
          STDEXEC::start(__op_);
        }
      }

      __op_t __op_;
    };