tracing-channel

Critical-path bench. Every instrumented operation, regardless of integration, is dispatched into its plugin through the diagnostic channels the Plugin base binds and subscribes to: apm:<id>:<operation>:start runs the store binding (bindStart) and :finish notifies the subscription (finish). This isolates that generic dispatch cost with a plugin whose handlers do nothing integration-specific, so it is measured once here instead of being folded into — and diluting — every per-integration plugin benchmark, which call their handler directly.