title: Flutter - Fixed position in a bidirectional scroll
body: <p>is there any way I can implement a bidirectional scroll list where a part of it has a fixed position?
  I mean, for example a table that has a legend in the top for each column, I want to keep that legend when I scroll up/down but I also want it to have functionality with the scroll right/left with the rest of the content.
  (I know how to implement a bidirectional scroll list, that is not what I am asking for)</p>