asio-backend [3]: simplify AsioRxCommunicator
- There is no need to use an rxcpp subject for sending messages. It
only brings the burden of thread-safety when different threads call
on_next
. - Outbound messages are posted to the io_context with
vtkAsioInternalsConnection::PostWrite
anyway which is thread-safe. - depends on async/paraview!260, async/paraview!262
Edited by Jaswant Panchumarti (Kitware)