Method operator()

cpp/src/arrow/util/async_generator.h:89–100

  struct LoopBody {
    struct Callback {
      Result<ControlFlow<>> operator()(const T& next) {
        if (IsIterationEnd(next)) {
          return Break();
        } else {
          auto visited = visitor(next);
          if (visited.ok()) {
            return Continue();
          } else {
            return visited;
          }
        }
      }

      Visitor visitor;
    };