在Json.NET序列化回调中使用StreamingContext参数有什么用？

I'm trying to understand what were the StreamingContext parameter supposed to contain in Json.NET Serialization Callbacks, first I thought you would allow me access to the current json tree that is being read, but it doesn't seem to that, I tried may arrangements of JSON objects, but with none of them I could get anything from the StreamingContext parameter.I'm trying to understand what were the Streamin