This is mostly the same as what's currently in the Ruby SDK here. Here are the main differences - others are mentioned in comments:
I've streamlined the API by moving support code into an Impl module and exception classes into Errors, so the landing page of the API docs clearly shows you the main things you need.
You can configure a few more things in the client constructor.
The parameter passed to the error handler will always be an exception, rather than a hash.
I had to fix the backoff logic again because the "threshold" behavior that I recently added did not really work as advertised. Now it does and there's an actual test for it.
This is mostly the same as what's currently in the Ruby SDK here. Here are the main differences - others are mentioned in comments:
Implmodule and exception classes intoErrors, so the landing page of the API docs clearly shows you the main things you need.