code: func Flush(ctx context.Context, tracer opentracing.Tracer) {
  	switch lsTracer := tracer.(type) {
  	case Tracer:
  		lsTracer.Flush(ctx)
  	case *tracerv0_14:
  		Flush(ctx, lsTracer.Tracer)
  	default:
  		emitEvent(newEventUnsupportedTracer(tracer))
  	}
  }
docs: // Flush forces a synchronous Flush.