Method process

test/anyflow/test_channel.cpp:63–67

struct MutableChannelInputProcessor : public GraphProcessor {
  virtual int process() noexcept override {
    enter_promise.set_value(::std::move(a));
    leave_future.get();
    return 0;
  }

  static ::std::promise<MutableChannelConsumer<::std::string>> enter_promise;
  static ::std::future<MutableChannelConsumer<::std::string>> enter_future;