There is no indication on the Stack Exchange thread that you have read or ingested the answers given there. There is no point spraying off the same question onto multiple platforms if you aren't then going to put the effort into indicating whether or not the answers have helped you.
Let me give you an analogy: Say you go out into the garden and pull up all the weeds. Then a few days later you complain because more weeds have grown. It takes time for the weeds to grow and "flushing" them at any particular point won't remove ones that grow in the future. Same with the serial port. You can't flush things that haven't arrived yet.