It seems like WaitFor[Single|Multiple]Object calls aren't reliable on pipes, especially
on the pipe opened for childSession access. The object can be marked as signaled even if
no data is available, making the connection laggy and unresponsive (nearly unusable in some
cases).
This patch works around that by using ReadFileEx() with overlapped instead of simple
ReadFile() and use asynchronous reads.
aebe9742e0