1.Coded up unit tests, please note some unit tests are marked as manual which are NOT meant to be ran manually

2. Separated Metrics and DeviceManager
3. Added Main method, no robust at all, but should work :)
4. See https://github.com/leozc/TCPMulportsServer for a tester
	modified:   multiplexingThrottler/SimplePerDataBlockThrottlerPolicyHandler.cs