Alert if Index is getting more than 10GB of incoming data

I am using below query to find size of index , how can I modify it to alert me if index is getting more than 10 GB of incoming data index=_internal [`set_local_host`] source=*license_usage.log* type="Usage" idx="*"| eval MB = round(b/1048576,2) | eval st_idx = st.": ".idx | timechart span=1d sum(MB) by st_idx | addtotals