pipe constant Null safety

1. Dart
2. dart:io
3. StdioType
4. pipe constant

StdioType class

1. Properties
2. hashCode
3. name
4. runtimeType
5. Methods
6. noSuchMethod
7. toString
8. Operators
9. operator ==
10. Constants
11. FILE
12. file
13. OTHER
14. other
15. PIPE
16. pipe
17. TERMINAL
18. terminal