public String getColumnWidth(Column<T, ?> column) {
        return columnWidths.get(column);
    }
Get the width of a {@link Column}.

@param column the column
@return the width of the column, or null if not set
@see #setColumnWidth(Column, double, Unit)
stroom-core-client-widget/src/main/java/com/google/gwt/user/cellview/client/AbstractCellTable.java