<PackageReference Include="System.Reactive" Version="6.0.2" />

ObservableQuery

using System.Linq.Expressions; using System.Runtime.CompilerServices; namespace System.Reactive { [System.Runtime.CompilerServices.NullableContext(1)] [System.Runtime.CompilerServices.Nullable(0)] internal class ObservableQuery { [System.Runtime.CompilerServices.Nullable(2)] protected object _source; protected Expression _expression; [System.Runtime.CompilerServices.Nullable(2)] public object Source { [System.Runtime.CompilerServices.NullableContext(2)] get { return _source; } } public Expression Expression => _expression; public ObservableQuery(object source) { _source = source; _expression = Expression.Constant(this); } public ObservableQuery(Expression expression) { _expression = expression; } } }