widthEstimator property
Optional explicit width estimator for cells whose true rendered size
can't be inferred by measuring map's raw value as plain text (e.g.
a chip's padding/border, a star rating's icon row, a switch's fixed
track size). Given the same T the column measures, return an
estimated unwrapped pixel width for that cell. Takes priority over
both map-based text measurement and the flat fallback used when
there's no map at all.
Implementation
final double Function(T data)? widthEstimator;