  /**
   * Creates a new object recording the production of the specified value at the given virtual time.
   *
   * @constructor
   * @param {Number} time Virtual time the value was produced on.
   * @param {Mixed} value Value that was produced.
   * @param {Function} comparer An optional comparer.
   */
  var Recorded = Rx.Recorded = function (time, value, comparer) {
    this.time = time;
    this.value = value;
    this.comparer = comparer || defaultComparer;
  };

  /**
   * Checks whether the given recorded object is equal to the current instance.
   *
   * @param {Recorded} other Recorded object to check for equality.
   * @returns {Boolean} true if both objects are equal; false otherwise.  
   */  
  Recorded.prototype.equals = function (other) {
    return this.time === other.time && this.comparer(this.value, other.value);
  };

  /**
   * Returns a string representation of the current Recorded value.
   *
   * @returns {String} String representation of the current Recorded value. 
   */   
  Recorded.prototype.toString = function () {
    return this.value.toString() + '@' + this.time;
  };
