Add framework instrumentation

[jcchavezs]

We need to provide framework integrations for zipkin. Priority frameworks are:

1. Symfony
2. Laravel
3. Silex
4. Guzzle http client

Ping @felixfbecker @beberlei

[felixfbecker]

Imo they should definitely be in a separate repo each. They should be able to get their own independent versioning. Noone uses all these frameworks at the same time, so they also shouldn't have to pull in code for it.

[jcchavezs]

Integration with Symfony: https://github.com/jcchavezs/zipkin-instrumentation-symfony

[jcchavezs]

For laravel, there are this libraries so far:

• https://github.com/laravelcloud/lar-trace by @jiangjianyong
• https://github.com/luoxiaojun1992/laravel-zipkin by @luoxiaojun1992
• https://github.com/luca-giardina/lara-zipkin by @luca-giardina

[andrei-dascalu]

Is this something to still look into? Laravel seems supported and Silex is quite dead.

There are some modern frameworks around (Symlex, Lumen, Spiral)

Lumen seems to have https://github.com/shlj/php-zipkin-lumen

[jcchavezs]

There is a PR for laravel. It would be really cool if we could add a test to make sure laravel works fine. Would you be up to do that?