Option to optimize file size

Refer to the following example code to see how to optimize file size. - **ExcludeUnusedStyles** Indicates whether to exclude user-defined but never used Cell styles, default value is false. - **ExcludeUnusedNames** Indicates whether to exclude user-defined but never used Define name, default value is false. - **ExcludeEmptyRegionCells** Indicates whether to exclude any empty cells(cells with no data or only style) outside the used data range.