Offer Plugin Interface to Support Additional Transport Layers

[pulltab]

tcpkali is a great tool for websockets and tcp, however, there are other transport layers that could benefit from the bench harness internal to tcpkali.

This feature request is for a plugin interface that would allow a user to define additional transports for use during testing.

[vlm]

Please check the https://github.com/machinezone/mzbench for a project with an open architecture.