Changed to Reference Bound type (#14)

Author: hishd

Sources/Networking/DataTranserService/NetworkDataTransferService.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public protocol NetworkDataTransferService {
+public protocol NetworkDataTransferService: AnyObject {
     typealias CompletionHandler<T> = (Result<T, NetworkDataTransferError>) -> Void
     typealias CompletionHandlerCollection<T> = (Result<ResponseData<T>, NetworkDataTransferError>) -> Void
     @available(macOS 10.15, *)