Will be nice to clear auth credentials. For example, I'm using a proxy that accepts options via username:

```
proxy.com:8080
user: wiliam_country_US
```

So, if I want to change the peer node, I change my username:

```
proxy.com:8080
user: wiliam_country_GB
```

But, I'm not changing the proxy, so electron has valid credentials and is not going to trigger `login` event.

I'm searching the way to clean auth settings so electron asks them again.
atom/browser/net/atom_url_request.h
api::URLRequest* delegate);
  void Terminate();
  bool Write(scoped_refptr<const net::IOBufferWithSize> buffer, bool is_last);
  void SetChunkedUpload(bool is_chunked_upload);
  void Cancel();
  void SetExtraHeader(const std::string& name, const std::string& value) const;
  void RemoveExtraHeader(const std::string& name) const;
  void PassLoginInformation(const base::string16& username,
                            const base::string16& password) const;
 protected:
  
  void OnAuthRequired(net::URLRequest* request,
                      net::AuthChallengeInfo* auth_info) override;
  void OnResponseStarted(net::URLRequest* request) override;
  void OnReadCompleted(net::URLRequest* request, int bytes_read) override;
  
  void OnContextShuttingDown() override;
 private:
  friend class base::RefCountedThreadSafe<AtomURLRequest>;
  explicit AtomURLRequest(api::URLRequest* delegate);
  ~AtomURLRequest() override;
  void DoInitialize(scoped_refptr<net::URLRequestContextGetter>,
                    const std::string& method,
                    const std::string& url);
  void DoTerminate();
  void DoWriteBuffer(scoped_refptr<const net::IOBufferWithSize> buffer,
                     bool is_last);
  void DoCancel();
  void DoSetExtraHeader(const std::string& name,
                        const std::string& value) const;