3 Need support for toggling echo and line buffering
4 - This needs to be communicated to pty owner somehow
5 > Second FD? Nominated data structure? Out of band data?
6 - API for the pty control?
7 > "_SysSetFileFlag"/"_SysGetFileFlag"?
8 Provides arbitary flags for each node
9 E.g. Terminal graphics mode, echo and buffering