SelectionHelpers: thread-checker fixes
Use asg::AsgMessagingForward
instead of raw MsgStream
pointer for
messaging. The latter is not guaranteed to be thread-safe as in the
general case, the MsgStream
of the "owner" is implemented as
thread-local.
Also remove the usage of MsgStream
entirely from SelectionReadHandle
(which itself seems entirely unused).
Enable thread-checker.
Edited by Frank Winklmeier