Ensure running unregisterDelegate.dispose() on main thread. (#19)

* Ensure running unregisterDelegate.dispose() on main thread

* Ensure dispose unregisterDelegate on main thread

Author: mongris

Sources/DataSources/RxHelper/ASDelegateProxy.swift

@@ -17,7 +17,13 @@ extension ObservableType {
         where DelegateProxy.ParentObject: ASDisplayNode {
 
             let proxy = DelegateProxy.proxy(for: object)
-            let unregisterDelegate = DelegateProxy.installForwardDelegate(dataSource, retainDelegate: retainDataSource, onProxyForObject: object)
+            
+            // ensure dispose unregisterDelegate on main thread
+            let unregisterDelegate = ScheduledDisposable(
+                scheduler: MainScheduler.instance,
+                disposable: DelegateProxy.installForwardDelegate(dataSource, retainDelegate: retainDataSource, onProxyForObject: object)
+            )
+            
             // this is needed to flush any delayed old state (https://github.com/RxSwiftCommunity/RxDataSources/pull/75)
             object.layoutIfNeeded()
 
@@ -49,7 +55,7 @@ extension ObservableType {
                     default:
                         break
                     }
-            }
+                }
 
             return Disposables.create { [weak object] in
                 subscription.dispose()