ProgressBar
@Composable
A bar which fills from the left as progress goes from 0 to 1, to an eighth of a cell.
It is one row high and DefaultProgressBarWidth cells wide unless modifier sizes it, for example with Modifier.width or Modifier.fillMaxWidth. The filled part is drawn in color, and the whole bar has the background trackColor, so that the part still to fill shows too. The bar covers whatever is below it, such as a border it is drawn over. A progress outside of 0 to 1 shows as the nearest end, and one which is not a number as empty.