docs: function hook(req, res, next) {
    var _end    = res.end;
    var _write  = res.write;
    //var _on     = res.on;
  
    res.write = function(chunk, encoding) {
      // ... other things
  
      // Call the original
      _write.call(this, chunk, encoding);
  
      // Note: in some cases, you have to restore the function:
      // res.write = _write;
    };
  
    res.end = function(chunk, encoding) {
      // ... other things
  
      // Call the original
      _end.call(this, chunk, encoding);
  
      // Note: in some cases, you have to restore the function:
      // res.end = _end;
    };
  
    return next();
  }