processExtraMetrics(ctx, payload) {
		// extra metrics (params and meta)
		if (isObject(ctx.action.metrics)) {
			// custom metrics def
			this.assignExtraMetrics(ctx, "params", payload);
			this.assignExtraMetrics(ctx, "meta", payload);
		}
	}
Decide and process extra metrics taking into account action definitions

@param {Context} ctx
@param {any} payload Object for assignment.

@private