Function withTrace

withTrace<T>(fn: (span: Span) => T, opts?: WithTraceOptions): T
Execute fn inside a new OpenTelemetry span, returning whatever fn returns.

The span is automatically named from the function (or caller location) unless overridden via opts.name. Errors are recorded on the span and re-thrown.

Cloudflare Workers caveat: performance.now() only advances after I/O in Workers (Spectre mitigation). Spans wrapping pure CPU work (no fetch, KV, R2, D1, etc.) will report a duration of 0 ms. Use withTrace for operations that involve at least one I/O call.
Type Parameters
- T
Parameters
- fn: (span: Span) => T
  The function to trace. Receives the active Span as its argument.
- Optionalopts: WithTraceOptions
  Optional tracing configuration.
Returns T
The return value of fn (or a Promise thereof).
Example
```
import { withTrace } from "@tigorhutasuhut/telemetry-js";

// Named function — span name is "fetchUser"
const user = await withTrace(async function fetchUser(span) {
  span.setAttribute("user.id", id);
  return db.users.find(id);
});

// Explicit name + attributes
const result = withTrace(
  (span) => compute(span),
  { name: "heavy-computation", attributes: { "input.size": "42" } },
);
```
- Defined in src/with-trace.ts:161