code: function compareFixesByRange(a, b) {
      return a.range[0] - b.range[0] || a.range[1] - b.range[1];
  }
docs: Compares items in a fixes array by range.
  @param {Fix} a The first message.
  @param {Fix} b The second message.
  @returns {int} -1 if a comes before b, 1 if a comes after b, 0 if equal.
  @private