Aggregate Client connection metrics.

[loserwang1024]

Search before asking

• I searched in the issues and found nothing similar.

Fluss version

0.7.0 (latest release)

Please describe the bug 🐞

As shown in #1531, not only server needs it, but also client need to aggregate connection metrics.

Currently, n client with m server nodes, will have O(m*n) connection metrics. This is too much cost.
If report aggregation metrics(avg, sum or max), only need O(n) connection metrics.

Solution

No response

Are you willing to submit a PR?

• I'm willing to submit a PR!