In the .NET InProcessRuntime we tried to minimize the amount of tasks
created. Unfortunately, this results in a deadlock when a send message
handler is attempting to SendMessage during the handling of the incoming
message.
The fix is to create a new task for delivering the message in the
message processing loop, which creates a new logical stack to run the
delivery, freeing the loop to process the next delivery request.
* Also fixes passing exceptions and cancellations back to the waiting
task.
* Also fixes a build slowdown on Windows due to uv and llama-cpp
Closes#5915
