Before, I am working on bumping Prometheus client to 0.12.0, but they introduce a breaking change, https://github.com/prometheus/client_java/pull/615, adopt the `OpenMetrics format`, which acquired all counters have `_total` suffix,
but our metrics now have these metrics, there are not satisfied with the OpenMetrics format, for example: - pulsar_connection_closed_total_count - pulsar_connection_created_total_count - pulsar_source_received_total_1min - system_exceptions_total_1min I want to discuss, Should we adapt the `OpenMetrics format`? If we want to be compatible with Open Metrics, I suggest adding metrics named `_total` in a release version like 2.10.0, and removing the origin metric in the next release like 2.11.0.
