Is your feature request related to a problem? Please describe.
Currently, the same run_name will be used if using "tracking" default setup shown in the docstring

Describe the solution you'd like
run_name should be automatically defined based on client identity and experiment run (job_id in the nvflare case)

Describe alternatives you've considered
Manually, configuring the run_name argument of MLFlowHandler would be too cumbersome as it would need to change for each experiment and site.

Additional context
Manually setting the run_name for each client works but is cumbersome and error-prone.