NodeJS domain in error object and circular structures

We start using error domain feature in NodeJS - http://nodejs.org/api/domain.html and get an issue. node-airbake tried to util.inspect err.domain which has circular structures and hang entire app for several minutes. There are two issues:
- It is not safe to use util.inspect without limiting depth or detecting circular references
- err.domain and few more related variables are useless for error reporting