Method fulfill

valdi_core/src/valdi_core/cpp/Utils/ResolvablePromise.cpp:36–56

        setCancelCallback([promise]() {
            // This captures a strong ref reference, which will form a cycle.
            // When this promise is fulfilled by upstream promise,
            // the callback is removed, and the cycle will break
            if (promise != nullptr) {
                promise->cancel();
            }
        });
    }
}

void ResolvablePromise::fulfill(Result<Value> result) {
    std::unique_lock<Mutex> lock(_mutex);
    if (!_result.empty()) {
        // A producer may legitimately settle asynchronously after cancel() already recorded the
        // synthetic canceled error; drop its result. Settling twice without a cancel is still a bug.
        SC_ASSERT(_canceled, _result.description());
        return;
    }

    _result = result;
    // clear after move because moved-from function is in "valid but unspecified" state
    auto callbacks = std::move(_callbacks);
    _callbacks = {};
    auto cancelCallback = std::move(_cancelCallback);
    _cancelCallback = {};