code: public Proxy setType( String type )
      {
          if ( this.type.equals( type ) || ( type == null && this.type.length() <= 0 ) )
          {
              return this;
          }
          return new Proxy( type, host, port, auth );
      }
docs: Sets the type of the proxy.
  
  @param type The type of the proxy, e.g. "http", may be {@code null}.
  @return The new proxy, never {@code null}.