React Native share file with custom extension

I have an application that generates files with .IGC extension. It is a text file actually. I am trying to share this files with react-native-share package. In iOS it is fine. But on Android, I need to convert file to base64. But this time, it generates file with .txt extension. I got file_name.IGC.txt. I use react-native-fs to convert base64. Here is the issue. How can I share my files with same extension? Thanks in advance.