Tracer does weak->Arc upgrade twice in hot path leading to bottleneck

[cijothomas]

Tracer holds a weakref to its TracerProvider and attempts to upgrade that to an Arc twice in the hot path - one during span start and then again during span end. This is affecting throughput due to contention.

This issue is already fixed for Logs, opening a new issue to track fixing the same for traces.

[TommyCpp]

Will take a look this week

[TommyCpp]

1. Make the span processor shutdown from any reference fix: make shutdown &self in span processor #1836
2. Add shutdown to sdk tracer provider feat: add shutdown in TracerProvider #1855
3. Remove global::shutdown_global_tracer_provider chore: remove the global::shutdown_tracer_provider function #2369
4. Now tracer provider can take a TracerProviderInner Arc pointer. feat: add shutdown in TracerProvider #1855

[cijothomas]

This is done. Closing the issue.