code: function wrapCallback(callback)
  {
    var stream = this;
  
    var wrapped = function(error, result)
    {
      return finisher.call(stream, error, result, callback);
    };
  
    return wrapped;
  }
docs: Wraps provided callback function
  allowing to execute snitch function before
  real callback
  
  @this    ReadableAsyncKit#
  @param   {function} callback - function to wrap
  @returns {function} - wrapped function