mouseOut property
Fires when the mouse leaves the graph. One parameter, event, is
passed to the function, containing common event information. If the
stickyTracking option is true, mouseOut
doesn't happen before the mouse enters another graph or leaves the
plot area.
API Docs: https://api.highcharts.com/highcharts/series.variablepie.events.mouseOut
Implementation
HighchartsCallback? mouseOut;