MQTT option for Sensor Status Telemetry

[tvgriffith]

On a reload of Home Assistant, the current status of the sensors are not retained by the MQTT server and become "unknown". Can an option be implemented to provide:-

1. Telemetry - Regular interval-based publishing of sensor status via MQTT.
2. On-Demand Requests - A way for the MQTT client to request sensor status updates as needed.

Thanks