ColumnSizingInfoState
class ColumnSizingInfoState(val startOffset: Double?, val startSize: Double?, val deltaOffset: Double?, val deltaPercentage: Double?, val isResizingColumn: Any?, val columnSizingStart: List<Pair<String, Double>>)
Transient state captured during a column resize gesture. All fields are null when no resize is in progress; isResizingColumn holds the column id (or false) when one is.