anchor.diff:  
   TIP: Policy instances are bound to a conversation, hence the same object will receive the response corresponding to the request.
   
  +```java
  +Object parseConfiguration(String jsonConfiguration) throws ConfigurationParseException;
  +```
  +
  +The final `IPolicy` method is used to parse JSON configuration into an arbitrary object configuration which will be passed in in its parsed form to `doApply`, where the implementor may cast it their native configuration object. This method should be regarded as a static, as it is only called at the point when a policy is registered.
  +
   ===== Indicating Successes
   
   If a policy determines that the conversation can continue, `chain.doApply` should be signalled. Any modifications you wish to pass onto the next policy should be completed and included in the invocation.
  
positive.code:       // using super.write().
        super.write(chunk);
      }
    };
  }
  ```
  
  IMPORTANT: Do not mutate an `IApimanBuffer` once handed over.
  
  ==== Performance Considerations
  
  
negative.code: 
  As a factor of the asynchronous nature of apiman, any exceptions that may occur during the operation of a policy should be caught and explicitly handed to `chain.doError`. If exceptions are left uncaught, then it is possible that they will be lost.
  
  ==== IData Policy
  
  Whilst standard policies are concerned only with the head of the conversation, it is also possible for policies to access and manipulate the body in transit. A data policy must implement the `IDataPolicy` interface.
  
  