Skeleton of Code for Creation Observable - distilled from my experience~ 😊

RxBlog-observable-skeleton.cs

using System.Reactive.Linq;

public class MyStateType {
}

IObservable<MyStateType> observable = Observable.Create<MyStateType>( observer => {

    // should be CancellationTokenSource
    // but use bool so it easier to understand
    bool stop = false;

    // initialize and start the processing
    // in another thread because you have to
    // "Return" first to create an observable
    // otherwise the thread will stuck here
    
    // (or use theOtherClass.AnEvent += myhandler here instead
    // if you are subscribing to another event)
    Task.Run( ()=>{
    
        var myStateVariable = new MyStateType();
    
        // some long running operation    
        while (!stop) // or !canceller.Token.IsCancellationRequested
        {
            Task.Delay(1000);
            
            observer.OnNext( myStateVariable );
        }    
    });

    // return function to call when observable was being destroyed
    return ()=> 
    {
        stop = true;        
        // or canceller.Cancel();
        // or theOtherClass.AnEvent -= myhandler
        
        
        // dispose external resource
        // manage state
    };

});