fix multi thread issue

Author: AMikettaHmmH

modules/swagger-codegen/src/main/resources/swift4/AlamofireImplementations.mustache

@@ -20,6 +20,9 @@ class AlamofireRequestBuilderFactory: RequestBuilderFactory {
 // Store manager to retain its reference
 private var managerStore: [String: Alamofire.SessionManager] = [:]
 
+// Sync queue to manage safe access to the store manager
+private let syncQueue = DispatchQueue(label: "thread-safe-sync-queue", attributes: .concurrent)
+
 open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
     required public init(method: String, URLString: String, parameters: [String : Any]?, isBody: Bool, headers: [String : String] = [:]) {
         super.init(method: method, URLString: URLString, parameters: parameters, isBody: isBody, headers: headers)
@@ -58,7 +61,9 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         let managerId:String = UUID().uuidString
         // Create a new manager for each request to customize its request header
         let manager = createSessionManager()
-        managerStore[managerId] = manager
+        syncQueue.async(flags: .barrier) {
+            managerStore[managerId] = manager
+        }
 
         let encoding:ParameterEncoding = isBody ? JSONDataEncoding() : URLEncoding()
 
@@ -112,7 +117,9 @@ open class AlamofireRequestBuilder<T>: RequestBuilder<T> {
         }
 
         let cleanupRequest = {
-            _ = managerStore.removeValue(forKey: managerId)
+            syncQueue.async(flags: .barrier) {
+                 _ = managerStore.removeValue(forKey: managerId)
+            }
         }
 
         let validatedRequest = request.validate()
@@ -314,7 +321,9 @@ open class AlamofireDecodableRequestBuilder<T:Decodable>: AlamofireRequestBuilde
         }
 
         let cleanupRequest = {
-            _ = managerStore.removeValue(forKey: managerId)
+            syncQueue.async(flags: .barrier) {
+                _ = managerStore.removeValue(forKey: managerId)
+            }
         }
 
         let validatedRequest = request.validate()