code: func NewDatadogCollector(addr, prefix string) (func(string) metricCollector.MetricCollector, error) {
  
  	c, err := statsd.NewBuffered(addr, 100)
  	if err != nil {
  		return nil, err
  	}
  
  	// Prefix every metric with the app name
  	c.Namespace = prefix
  
  	return NewDatadogCollectorWithClient(c), nil
  }
docs: // NewDatadogCollector creates a collector for a specific circuit with a
  // "github.com/DataDog/datadog-go/statsd".(*Client).
  //
  // addr is in the format "<host>:<port>" (e.g. "localhost:8125")
  //
  // prefix may be an empty string
  //
  // Example use
  //  package main
  //
  //  import (
  //  	"github.com/afex/hystrix-go/plugins"
  //  	"github.com/afex/hystrix-go/hystrix/metric_collector"
  //  )
  //
  //  func main() {
  //  	collector, err := plugins.NewDatadogCollector("localhost:8125", "")
  //  	if err != nil {
  //  		panic(err)
  //  	}
  //  	metricCollector.Registry.Register(collector)
  //  }