When multiple parents exist, the union of their baggage values must be propagated to the child `Span`. See https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/opentracing.md#start-a-new-span
When multiple parents exist, the union of their baggage values must be propagated to the child
Span.See https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/compatibility/opentracing.md#start-a-new-span