<PackageReference Include="System.Reactive" Version="6.0.0-preview.9" />

System.Reactive.Linq.IQbservable

public interface IQbservable
Provides functionality to evaluate queries against a specific data source wherein the type of the data is not specified.
namespace System.Reactive.Linq { public interface IQbservable { Type ElementType { get; } Expression Expression { get; } IQbservableProvider Provider { get; } } }