Update integrations & examples around performance monitoring

[cleptric]

Summary

With the addition of StartTransaction, we should update our integrations to support performance monitoring out of the box.

• net/http
• Echo
• FastHTTP
• Gin
• Fiber
• Iris
• Negroni

We will also need to update or docs, I'll use this issue to track this work as well.

[uded]

Any progress with Gin? We are using custom code now, not a great way...

[aldy505]

Some updates:

• Echo: feat(performance): start transaction for echo middleware/integration #722
• Fasthttp: feat(performance): start transaction for fasthttp integration #723
• Fiber: Fiber integration #795

I'll do the rest next (Iris, Martini, Negroni), I haven't use them before but I'll give it a try.

[cleptric]

You can skip Martini. Will remove it, no updates for 8 years. https://github.com/go-martini/martini

[aldy505]

Great. Assign this to me, maybe? 😝

[cleptric]

PRs are welcome.

[aldy505]

Should we close this? @cleptric