<PackageReference Include="System.Reactive" Version="6.0.1" />

System.Reactive.Linq.ObservableImpl.TakeUntilPredicate<TSource>

sealed class TakeUntilPredicate<TSource> : Producer<TSource, TakeUntilPredicateObserver<TSource>>
Relays items to the downstream until the predicate returns true.
namespace System.Reactive.Linq.ObservableImpl { } namespace System.Reactive.Linq.ObservableImpl { }