IConnectableObservable<T>
Represents an observable wrapper that can be connected and disconnected from its underlying observable sequence.
            
                using System.Runtime.CompilerServices;
namespace System.Reactive.Subjects
{
    [System.Runtime.CompilerServices.NullableContext(1)]
    public interface IConnectableObservable<[System.Runtime.CompilerServices.Nullable(2)] out T> : IObservable<T>
    {
        IDisposable Connect();
    }
}