Multiple channels for a single session

[Игорь Коваленко <igor.a.kovalenko@xxxxxxxxx>]

Hello!
I'm developing ssh-server and I need that one session can create two
channels - one with sftp subsystem and one with shell subsystem.
These channels have to work simultaneously. Shell subsystem must process
special commands from user and simultaneously user could transfer files.
Documentation says "You cannot use a single session (or channels for a
single session) in several threads at the same time."
Does this mean that I need to do tasks for both of my channels in one
thread and I need some kind of scheduling between them?
Or is it better to create different sessions for shell and for sftp tasks?