Enable proxy NSSession

    NSString* proxyHost = @"localhost";
    NSNumber* proxyPort = [NSNumber numberWithInt: 8888];
   
    // Create an NSURLSessionConfiguration that uses the proxy
    NSDictionary *proxyDict = @{
                                @"HTTPEnable"  : [NSNumber numberWithInt:1],
                                (NSString *)kCFStreamPropertyHTTPProxyHost  : proxyHost,
                                (NSString *)kCFStreamPropertyHTTPProxyPort  : proxyPort,
                               
                                @"HTTPSEnable" : [NSNumber numberWithInt:1],
                                (NSString *)kCFStreamPropertyHTTPSProxyHost : proxyHost,
                                (NSString *)kCFStreamPropertyHTTPSProxyPort : proxyPort,
                                };
   
    configuration.connectionProxyDictionary = proxyDict;