ChannelFactory创建和销毁昂贵
- involves内部创建ChannelFactory<T>，每个proxy都持有一个ChannelFacotry的private field。ChannelFactory的生命周期由proxy完全控制。
- 构造ContractDescription树
- 反射所有需要的CLR类型
- 构造channel stack
- dispose所有的资源
在3.0SP1和3.5下两个主要的性能提升：
- ChannelFacotry缓存在ClientBase<T>里
- Channel管理逻辑改进
改进：
核心：ClientBase<T>的性能提升依靠缓存ChannelFactory对象
ChannelFacotry的生命周期不在被proxy控制，使用MRU cache（most recently used）。cache size为32（固定的）
· In the constructor of ClientBase<T>, a lookup is performed to find amatched ChannelFactory in the cache.
· If found, the ref-count of the ChannelFactory is incremented. Otherwise, a new ChannelFactory is created based on the settings.
· Before the inner channel (the transparent proxy) of ClientBase<T> is created, the caching logic for the current ClientBase<T> can be disabled if other public properties (such as ChannelFactory, Endpoint, and ClientCredentials) are accessed.
· Once the innerchannel if created successfully, the ChannelFactory object for the ClientBase<T> is added to the cache if it’s not grabbed from the cache and caching is not disabled.
