[FEATURE REQUEST] Add a `Throughput` in the Summary

[kataras]

Hello @rogerwelin,

First of all I have to say that this is a great project with clean source code, I was able to understand the code flow very quickly, good job!

I just want to add a Throughput label in the Summary section of the results output. I think it's quite useful for us, who develop web frameworks, to see that number right away. Also, you can move the CLI part package main on a "./cmd/cassowary" directory so we can use the github.com/rogewelin/cassowary package as a library too to take the results directly. I know that you have json output option too but it will require from us to download executable based on the host OS, then exec.Cmd, then read the json file and unmarshal it which it is quite slow operation and requires many steps that can fail.

• https://en.wikipedia.org/wiki/Measuring_network_throughput

Thanks again,
Gerasimos Maropoulos. Author of Iris web framework

[rogerwelin]

@kataras Thanks for your encouraging words, definitely motivates me to improve the project.

I will add throughput as a to-do.

You're definitely right about moving out the CLI part so the rest can be used as a library. I did not envision the project to be used as more than a cli tool but I definitely see the use case here.

About the json output as a file; I think adding a new method that just returns the struct may be the way to go

[kataras]

You're welcome @rogerwelin, it's my honor!

I've just pushed the first PR in this repository as well! I could help you structuring your project (including some use cases I find you duplicate code) if you let me to.