Conceptual differences between the GDK and Steamworks

MyClass::SimpleContextExample()
{
    // ...
    struct MyContext 
    {
        MyHandle_t handle;
        std::shared_ptr<MyClass> instance;
    }

    // Assume myHandle is a variable containing the handle you'll need in your call function.
    auto contextPtr = std::unique_ptr<MyContext>(new MyContext{ myHandle, shared_from_this() });
    XAsyncBlock async = std::make_unique<XAsyncBlock>();
    async->context = contextPtr.get(); 
    async->callback = [](XAsyncBlock *async)
    {
        std::unique_ptr<XAsyncBlock> asyncBlockPtr{ asyncBlock }; // Take over ownership of the XAsyncBlock*        
        std::unique_ptr<MyContext> contextPtr{ static_cast<MyContext*>(asyncBlock->context) }; // Take over ownership of the context.        

        auto handle = contextPtr->handle;
        // You can now use your handle for other API calls.
    };

    HRESULT hr = SomeAsyncFunction(arg1, arg2, asyncBlock.get());
    if (SUCCEEDED(hr))
    {
        // The call succeeded, so release the std::unique_ptr ownership of XAsyncBlock* and context* 
        // since the callback will take over ownership.
        // If the call fails, the std::unique_ptr will keep ownership and delete the XAsyncBlock* and context block.
        asyncBlock.release();
        contextPtr.release();
    }
}