code: func WithTraceID128Bit(val bool) TracerOption {
  	return func(o *Tracer) error {
  		if val {
  			o.generate = idgenerator.NewRandom128()
  		} else {
  			o.generate = idgenerator.NewRandom64()
  		}
  		return nil
  	}
  }
docs: // WithTraceID128Bit if set to true will instruct the Tracer to start traces
  // with 128 bit TraceID's. If set to false the Tracer will start traces with
  // 64 bits.