Avoid race condition

SignalServiceKit/src/Loki/API/Onion Requests/OnionRequestAPI.swift

@@ -284,7 +284,7 @@ public enum OnionRequestAPI {
     internal static func sendOnionRequest(with payload: JSON, to destination: Destination, isJSONRequired: Bool = true) -> Promise<JSON> {
         let (promise, seal) = Promise<JSON>.pending()
         var guardSnode: Snode!
-        DispatchQueue.global(qos: .userInitiated).async {
+        SnodeAPI.workQueue.async { // Avoid race conditions on `guardSnodes` and `paths`
             buildOnion(around: payload, targetedAt: destination).done2 { intermediate in
                 guardSnode = intermediate.guardSnode
                 let url = "\(guardSnode.address):\(guardSnode.port)/onion_req"