Ensure the completion: callback is always invoked, regardless of th…

…e scenario

Sources/PubNub/Networking/Request/Request.swift

@@ -101,7 +101,18 @@ final class Request {
 
   deinit {
     PubNub.log.debug("Request Destroyed \(requestID)")
-
+
+    let currentState = atomicState.lockedRead { $0 }
+    let taskState = currentState.taskState
+
+    // Ensure that the response is always delivered to the caller. This situation could occur if the task is created
+    // but not yet resumed, and the session is invalidated in the meantime.
+    if taskState == .initialized {
+      let error = PubNubError(.clientCancelled)
+      atomicState.lockedWrite { $0.error = error }
+      finish(error: error)
+    }
+
     atomicState.lockedWrite { $0.purgeAll() }
   }