code: function (opt) {
      if (typeof opt !== "object" || opt === null) {
          opt = {};
      }
      if (typeof opt.tag !== "string") {
          opt.tag = null;
      }
      if (typeof opt.encoding !== "string") {
          opt.encoding = "utf8";
      }
  
      //Extends the readable stream
      stream.Readable.call(this, {encoding: opt.encoding});
  
      this._tag = (typeof opt.tag === "string") ? opt.tag.trim() : null;
      this._level = labels.length;
      this._disabled = false;
  
      //Default message format
      this._format = function (tag, label, text) {
          let list = [];
          if (tag) {
              //Add the tag if it is provided
              list.push("[" + tag + "]");
          }
          list.push("[" + timestamp("YYYY-MM-DD hh:mm:ss") + "]");
          list.push("[" + label.toUpperCase() + "]");
          list.push(text.trim());
          return list.join(" ");
      };
  
      return this;
  }
docs: Logty readable stream