v4 library feedback thread

[cep21]

Hi!

I'm thinking about what to modify for the v4 version of the library. Here is a feedback thread for all to contribute.

Some ideas off the top of my head:

• Remove the "/v3" root directory I needed to support projects that weren't on go modules. Use git tags instead
• Move statsd implementation to another library (#113 )
• Add ctx to the stats interfaces (#108 )
• Make the "zero" value "off" for configuration, rather than the defaults (See #114 )
• Make a common "circuit check" interface for people to add things like (#34 ) and move all the checks we currently have (concurrency, timeout, etc) into their own interface implementation
• Move benchmarks to their own repo

Do people have other thoughts on things they would change?