Add description to request and response and version to the API.

[rmsj]

Change the method signature for Response, Request and the NewAPI one, to add version.

[a-h]

This change would break everyone's existing code - i.e. if they upgrade the package, they'll get compilation errors.

I'm sure there's a way to add the version without breaking existing code, e.g. by using a WithVersion option.

Is there an issue driving this, or is it just a case of not liking the existing API design?

Thanks!

[rmsj]

I see.
I've updated the changes following your idea with the option function. This it keeps backward compatibility with current users.
Let me know what you think.

Thank you for your work on this project.