Function tower_sampler 

pub fn tower_sampler(
    labels: impl Fn(&str) -> Option<BlockLabel> + Send + Sync + 'static,
) -> Arc<dyn Fn() -> Result<Vec<PaneStat>> + Send + Sync> 

The live sampler: Tower’s sample of this machine, with each pane named by labels (a pane labels doesn’t know, such as one that was closed, is left out).