Have a handle_init / handle_destroy function and trait

[ahayzen-kdab]

Currently there is no way to perform any tasks at creation of the object that require access to the CppObj. (eg starting a background thread that takes the update_requester).

There also isn't a way to tidy up when the object is deconstructed, eg closing a thread / disconnect from db / network.

Add a HandleInit / HandleDestroy trait and method similar to handle_property_change, which is triggered by in the constructor / deconstructor of the object.

• HandleInit / HandleConstructor trait
• HandleDestroy / HandleDeconstructor trait

[ahayzen-kdab]

This is less relevant now, you can use the Default and Drop for Rust fields and properties. If you needed the C++ context. Then you could create a Rust invokable that is triggered by onCompleted/onDestructed.