role progressbar

Progress bar draft v0.1.0

Shows how far a task has progressed, or that it is in progress when its length is unknown.

A progress bar fills a track from start to end as a task advances: an upload, an export, the steps of a setup. It has a visible label naming the task and, when the progress can be measured, an optional value in percent. When the length is unknown, the bar is indeterminate: a segment moves along the track to say that something is happening. It only reports: a progress bar is never a control.