code: function introduce(fn, options) {
    var has = Object.prototype.hasOwnProperty;
  
    for (var key in options) {
      if (has.call(options, key)) {
        fn[key] = options[key];
      }
    }
  
    return fn;
  }
docs: Introduce options to the logger function.
  
  @param {Function} fn Calback function.
  @param {Object} options Properties to introduce on fn.
  @returns {Function} The passed function
  @public