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.
Under windows you can connect to a child session by requesting a named pipe to
the local server, and then do some RDP on this named pipe.
The protocol is like for /vmconnect with CredSSP, then Nego and then the "normal"
workflow for a connection. For CredSSP we force the usage of NTLM for the Negociate
SSPI, and the credentials are empty.
