Function instrumentWorkflow

instrumentWorkflow(
    opts?: InstrumentWorkflowOptions,
): <T extends new (...args: any[]) => any>(
    target: T,
    _context: ClassDecoratorContext<T>,
) => T
TC39 class decorator that instruments a Cloudflare Workflow with OpenTelemetry tracing.

Intercepts the run method to:
1. Initialise the SDK (handles fresh isolates after hibernation)
2. Auto-extract traceparent from event.payload for cross-workflow propagation
3. Create a root workflow.run span wrapping the entire execution
4. Wrap the step object with traced versions of do, sleep, and sleepUntil — nested step calls automatically become children of the outer step's span
Parameters
- opts: InstrumentWorkflowOptions = {}
  SDK configuration. env falls back to this.env from WorkflowEntrypoint at runtime.
Returns <T extends new (...args: any[]) => any>(
target: T,
_context: ClassDecoratorContext<T>,
) => T
A TC39 class decorator.
Example
```
import { instrumentWorkflow } from "@tigorhutasuhut/telemetry-js";

@instrumentWorkflow({ serviceName: "my-workflow" })
export class MyWorkflow extends WorkflowEntrypoint {
  async run(event: WorkflowEvent, step: WorkflowStep) {
    await step.do("fetch-data", async () => { ... });
  }
}
```
- Defined in src/runtimes/cloudflare/workflow.ts:171