code: function processExtraMetrics(ctx, payload) {
  	// extra metrics (params and meta)
  	if (_.isObject(ctx.action.metrics)) {
  		// custom metrics def
  		assignExtraMetrics(ctx, "params", payload);
  		assignExtraMetrics(ctx, "meta", payload);
  	}
  }
docs: Decide and process extra metrics taking into account action definitions
  
  @param {Context} ctx
  @param {any} payload Object for assignment.
  
  @private