Filter attributes at rest module

[Mikhail Gaidamaka]

Hi, all!

I'm using rest module to connect to my java restful service with json 
format request.

It works good, but i get troubles with EAP-TLS - it tries to encode ALL 
request content. How I can skip unused attributes (EAP-Message and other 
specific attrs).

I have tried to use attr_filter module, but it do 'noop'.

How I can limit attributes, that will be encoded to json?