"virtual void onStateChanged(int32_t a0, bool a1) noexcept = 0;";
"virtual void onStateChangedWithoutArgs() noexcept = 0;";
"virtual void onStateChangedFoo(Foo foo) noexcept = 0;";
r#"struct C_SomeObserver {
    void *opaque;
    //! call by Rust side when callback not need anymore
    void (*C_SomeObserver_deref)(void *opaque);

    void (*onStateChanged)(int32_t a0, char a1, void *opaque);

    void (*onStateChangedWithoutArgs)(void *opaque);

    void (*onStateChangedFoo)(FooOpaque * foo, void *opaque);

};"#;

"void f1(std::unique_ptr<SomeObserver> cb) noexcept;";

r#"template<bool OWN_DATA>
    inline void ClassWithCallbacksWrapper<OWN_DATA>::f1(std::unique_ptr<SomeObserver> cb) noexcept
    {

        C_SomeObserver tmp = SomeObserver::to_c_interface(cb.release());
        const struct C_SomeObserver * const a0 = &tmp;

        ClassWithCallbacks_f1(this->self_, std::move(a0));
    }"#;

"void ClassWithCallbacks_f1(ClassWithCallbacksOpaque * const self, const struct C_SomeObserver * const cb);";