如何在进行异步调用时关闭 SOAP 客户端

我正在异步调用 soap 服务，但卡在需要关闭 soap 客户端连接的位置。上一篇文章也没有太多帮助： 如何使用异步调用 WCF 关闭客户端代理

以下是我到目前为止的代码。

下面的方法（GetFieldList（....）调用泛型方法ApiClient.GetResponse（....），其中包含请求参数和要调用的服务

 public async Task<ServiceReference.GetFieldListResponse> GetFieldList(string identifier)
    {
        var request = new GetFieldListRequest
        {
            Header = new Header {Username = ApiSettings.Instance.ApiToken},
            AGroup = "",
            IdType = "",
            Id = ""
        };
        var response = await ApiClient.GetResponse(request, (c) => c.GetFieldListAsync(request.Header, request.Id, request.IdType, request.AGroup));
        return response;
    }

在下面的方法中，我已经注释掉了 finally 块，因为在向调用方法返回响应之前连接已关闭。

 public class ApiClient
 {
    public static TResponse GetResponse<TResponse, TRequest>(TRequest request, 
            Func<SoapClient, TResponse> handler,
            string apiMethodName = "")
    where TResponse : class
    {
        Debug.WriteLine("Calling: " + typeof(TRequest).Name);
        if (string.IsNullOrEmpty(apiMethodName))
        {
            apiMethodName = typeof(TRequest).Name.Replace("Request", string.Empty);
        }
       // creates a soap connection
        var client = WebServiceClient.CreateServiceInstance();
        TResponse response = null;
        try
        {
            //webservice call is invoked here
            response = handler(client);
        }
        catch (FaultException exception)
        {
            throw new ApiException(string.Format("Api error on {0}.", apiMethodName), exception);
        }
         //if this finally block is not commented, connection is closed before a response was returned to the calling method.
        //finally
        //{
        //  client.Close();
        //}
        return response;
    }
}

知道我错过了什么吗？谢谢