scylladb
Instrument driver with OpenTelemetry tracing
In order to increase driver's observability, it has been instrumented with OTel tracing. Requests, speculative executions and particular retries are covered with appropriate spans, which are filled with informative tags. The tracing incurs no overhead by default (when off), and bearable overhead when on. The PR contains (not many yet) tests and a Zipkin-based example.
Some of the tests are failing. Those should be fixed by: https://github.com/zpp-2021-telemetry/java-driver/pull/10 - please look if this PR could be simplified (the reason it wasn't merged was that it was a bit too complex to understand and not documented well enough).
Minor nit: formatting of commit messages: there shouldn't be a . at the end and line length of the body of the commit message shouldn't be longer than 72 characters (title no longer than 50 characters).
After long adventures with failing tests, the PR is finally ready for last review.
@avelanarius the requested fixes regading boundValues and partitionKey have been added.