Attaching HttpApi spans to NextJS (aka @vercel/otel)

export const TracingLayer = Layer.unwrapEffect(
  Effect.gen(function* () {
    yield* Effect.log("Building tracing layer")

    const serviceName = yield* Config.string("OTEL_SERVICE_NAME")
    const url = yield* Config.string("OTEL_EXPORTER_OTLP_ENDPOINT")
    const headersFromConfig = yield* Config.string("OTEL_EXPORTER_OTLP_HEADERS").pipe(Config.withDefault(""))
    const headers = yield* Schema.decodeUnknown(HeadersSchema)(headersFromConfig)

    return OtlpTracer.layer({
      url,
      headers,
      resource: { serviceName },
    })
  })
)