Identify usages of TrySetSingle that are safe to be converted to SetSingle and .Disposable = ... eventually.

Rx.NET/Source/src/System.Reactive/Concurrency/Scheduler.Services.Emulation.cs

@@ -377,7 +377,7 @@ namespace System.Reactive.Concurrency
                 _nextDue = _period;
                 _runState = Running;
 
-                Disposable.TrySetSingle(ref _task, _scheduler.Schedule(this, _nextDue, static (@this, a) => @this.Tick(a)));
+                Disposable.SetSingle(ref _task, _scheduler.Schedule(this, _nextDue, static (@this, a) => @this.Tick(a)));
                 return this;
             }
 

Rx.NET/Source/src/System.Reactive/Linq/Observable/AppendPrepend.cs

@@ -136,7 +136,7 @@ namespace System.Reactive.Linq.ObservableImpl
                     if (_append)
                     {
                         var disposable = _scheduler.ScheduleAction(this, AppendValue);
-                        Disposable.TrySetSingle(ref _schedulerDisposable, disposable);
+                        Disposable.SetSingle(ref _schedulerDisposable, disposable);
                     }
                     else
                     {

Rx.NET/Source/src/System.Reactive/Linq/Observable/GetEnumerator.cs

@@ -32,7 +32,7 @@ namespace System.Reactive.Linq.ObservableImpl
             //
             // [OK] Use of unsafe Subscribe: non-pretentious exact mirror with the dual GetEnumerator method.
             //
-            Disposable.TrySetSingle(ref _subscription, source.Subscribe/*Unsafe*/(this));
+            Disposable.SetSingle(ref _subscription, source.Subscribe/*Unsafe*/(this));
             return this;
         }
 

Rx.NET/Source/src/System.Reactive/Linq/Observable/SkipUntil.cs

@@ -36,7 +36,7 @@ namespace System.Reactive.Linq.ObservableImpl
 
             public void Run(SkipUntil<TSource, TOther> parent)
             {
-                Disposable.TrySetSingle(ref _otherDisposable, parent._other.Subscribe(new OtherObserver(this)));
+                Disposable.SetSingle(ref _otherDisposable, parent._other.Subscribe(new OtherObserver(this)));
                 Run(parent._source);
             }