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

Pattern<TSource1, TSource2, TSource3, TSource4, TSource5, TSource6, TSource7, TSource8>

public class Pattern<TSource1, TSource2, TSource3, TSource4, TSource5, TSource6, TSource7, TSource8> : Pattern
Represents a join pattern over eight observable sequences.
public Pattern<TSource1, TSource2, TSource3, TSource4, TSource5, TSource6, TSource7, TSource8, TSource9> And<TSource9>(IObservable<TSource9> other)

Creates a pattern that matches when all nine observable sequences have an available element.

public Plan<TResult> Then<TResult>(Func<TSource1, TSource2, TSource3, TSource4, TSource5, TSource6, TSource7, TSource8, TResult> selector)

Matches when all observable sequences have an available element and projects the elements by invoking the selector function.