title: Using go-kit logger api missing methods
body: <p>I want to use the logger from <a href="https://github.com/go-kit/kit/tree/master/log" rel="nofollow noreferrer">go kit</a> repository and I saw that
  that the author provided also <a href="https://github.com/sirupsen/logrus" rel="nofollow noreferrer">logrus</a> API/factory , while trying to test it with some common API functionality of logrus like ,<code>withFields</code> and <code>error</code> / <code>info</code> / <code>panic</code> etc
  I couldn't use them only log
  Any idea how can I add the missing log functionality ?</p>
  
  <p><a href="https://github.com/sirupsen/logrus#fields" rel="nofollow noreferrer">logrus.WithField</a> API.</p>
  
  <p>this is what I miss </p>
  
  <pre><code>  log.WithFields(log.Fields{
      "animal": "walrus",
    }).Info("A walrus appears")
  </code></pre>
  
  <p>and also the info / error / debug etc</p>
  
  <p>This is what I've tried </p>
  
  <pre><code>package main
  
  import (
     log "github.com/go-kit/kit/log/logrus"
     "github.com/sirupsen/logrus"
  )
  
  func main() {
  
     logrusLogger := logrus.New()
  
     logrusLogger.Formatter = &amp;logrus.JSONFormatter{TimestampFormat: "02-01-2006 15:04:05"}
     logger := log.NewLogrusLogger(logrusLogger)
  
      logger.Log("hello", "world”)  //working
  
     logger.WithFields(    //doesnt work
  
      logger.Info(      //doesnt work
  
  }
  
  </code></pre>
  
  <p>The logger is type <code>logrus</code> but I cannot use <code>withFields</code> OR <strong>info/error/debug</strong> etc, any idea what am I missing here? 
  as the log kit create some factory is there a way to use the logrus api ?</p>