EndpointUserConfig.AddEndpoint方法存在并发问题

[colin-chang]

aliyun-openapi-net-sdk/aliyun-net-sdk-core/Regions/EndpointUserConfig.cs

Line 16 in a2c710b

if (!endpoints.ContainsKey(key))

上面代码中 endpoints 使用了非线程安全字典 Dictionary<string, ProductDomain>。在字典中查询key过程中其他线程对字典进行修改会导致InvalidOperationException，异常堆栈信息如下：

System.InvalidOperationException: Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct.
   at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
   at Aliyun.Acs.Core.Regions.EndpointUserConfig.AddEndpoint(String product, String regionId, String domain)

建议将 endpoints 类型修改为线程安全的 ConcurrentDictionary<string, ProductDomain> 修复此问题 @AxiosCros