Statistics collection using Python API

[Vivek Sharma]

Adding for easier reference for others who might be interested in pulling statistics from Trex and are new to Python Automation APIs for Tres.

Ref: https://trex-tgn.cisco.com/trex/doc/trex_astf.html#_tutorial_python_automation_v2_47_and_up

Good example to begin with:

https://github.com/cisco-system-traffic-generator/trex-core/blob/master/scripts/automation/trex_control_plane/interactive/trex/examples/astf/astf_example.py

This example walks through 

- connecting to the trex server

- Resetting the ports

- loading the profile ( if profile has latency flag set, one can also get latency stats)

- Clearing stats

- Starting traffic

- Retrieving stats using get_stats() API in dictionary format

- Disconnect from server

Other references found useful:

https://trex-tgn.cisco.com/trex/doc/cp_astf_docs/genindex.html