呼叫外部dll時會發生 'big5' is not a supported encoding name. For information on defining a custom encoding, see the documentation for the Encoding.RegisterProvider method. (Parameter 'name')
解決方式：
https://harry-lin.blogspot.com/2019/05/net-core-big5.html
步驟一：Install-Package System.Text.Encoding.CodePages
步驟二：Encoding Provider註冊即可使用。(如為 ASP .NET Core Web 可在Startup進行註冊)
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);