Add async_added_to_hass method to request update at startup so as to …

…avoid waiting for scan interval

custom_components/poolmath/sensor.py

@@ -84,6 +84,10 @@ def __init__(self, hass, entry, name, poolmath_client, async_add_entities_callba
 
         self._async_add_entities_callback = async_add_entities_callback
 
+    async def async_added_to_hass(self):
+        """Request an update to bypass scan_interval at startup."""
+        self.async_schedule_update_ha_state(True)
+
     @property
     def name(self):
         """Return the name of the sensor."""