Merge pull request #5 from readdle/fix/fix-url-session-behaviour-task-fatal

URLSession fixes

Author: albertaleksieiev

Foundation/NSString.swift

@@ -27,7 +27,11 @@ func NSLocalizedString(_ key: String,
                        bundle: Bundle = Bundle.main,
                        value: String = "",
                        comment: String) -> String {
-    return bundle.localizedString(forKey: key, value: value, table: tableName)
+    #if os(Android)
+        return key
+    #else
+        return bundle.localizedString(forKey: key, value: value, table: tableName)
+    #endif
 }
 
 #if os(OSX) || os(iOS)

Foundation/URLSession/TaskRegistry.swift

@@ -115,4 +115,8 @@ extension URLSession._TaskRegistry {
         }
         return b
     }
+    
+    func containsBehaviour(for task: URLSessionTask) -> Bool {
+        return behaviours[task.taskIdentifier] != nil
+    }
 }

Foundation/URLSession/URLSession.swift

@@ -546,6 +546,10 @@ internal extension URLSession {
     }
 
     func behaviour(for task: URLSessionTask) -> _TaskBehaviour {
+        guard taskRegistry.containsBehaviour(for: task) else {
+            return .noDelegate
+        }
+        
         switch taskRegistry.behaviour(for: task) {
         case .dataCompletionHandler(let c): return .dataCompletionHandler(c)
         case .downloadCompletionHandler(let c): return .downloadCompletionHandler(c)