code: function(err, httpRes, body) {
  		if (err) _callback(err)
  		else {
  			try { var res = JSON.parse(body) }
  			catch(err) { _callback(null, body) }
  
  			if (httpRes && httpRes.statusCode !== 200) {
  				maybeRetry(res, IOD, IODOpts, apiType, _callback)
  			}
  			else _callback(null, res)
  		}
  	}
docs: Callback for handling request.
  Errors if response from IOD server is not 200.
  Attempts to JSON parse response body on success, returns original body if
  fail to parse.
  
  @param {*} err - Request error
  @param {Object} httpRes - Request http response object
  @param {*} body - Request body