vector-im/element-x-ios/issues/53 - Adopt MainActors, dispatch heavy operations do detached tasks and ensure combine publisher call back on the right queue

ElementX/Sources/Services/Timeline/RoomTimelineController.swift

@@ -31,7 +31,10 @@ class RoomTimelineController: RoomTimelineControllerProtocol {
         self.mediaProvider = mediaProvider
         self.memberDetailProvider = memberDetailProvider
         
-        self.timelineProvider.callbacks.sink { [weak self] callback in
+        self.timelineProvider
+            .callbacks
+            .receive(on: DispatchQueue.main)
+            .sink { [weak self] callback in
             guard let self = self else { return }
             
             switch callback {

ElementX/Sources/Services/Timeline/RoomTimelineControllerProtocol.swift

@@ -18,6 +18,7 @@ enum RoomTimelineControllerError: Error {
     case generic
 }
 
+@MainActor
 protocol RoomTimelineControllerProtocol {
     var timelineItems: [RoomTimelineItemProtocol] { get }
     var callbacks: PassthroughSubject<RoomTimelineControllerCallback, Never> { get }

ElementX/Sources/Services/Timeline/RoomTimelineProviderProtocol.swift

@@ -18,6 +18,7 @@ enum RoomTimelineProviderError: Error {
     case generic
 }
 
+@MainActor
 protocol RoomTimelineProviderProtocol {
     var callbacks: PassthroughSubject<RoomTimelineProviderCallback, Never> { get }
     

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineItemFactory.swift

@@ -9,6 +9,7 @@
 import Foundation
 import UIKit
 
+@MainActor
 struct RoomTimelineItemFactory {
     private let mediaProvider: MediaProviderProtocol
     private let memberDetailProvider: MemberDetailProviderProtocol

ElementX/Sources/Services/Timeline/TimelineItems/RoomTimelineViewFactory.swift

@@ -8,6 +8,7 @@
 
 import Foundation
 
+@MainActor
 struct RoomTimelineViewFactory {
     func buildTimelineViewFor(_ timelineItem: RoomTimelineItemProtocol) -> RoomTimelineViewProvider {
         switch timelineItem {