code: function readFile(filePath, opts, callback, count){ // callback(err)
      if(arguments.length===2){
          callback = arguments[1];
          opts = null;
      }
      if(typeof callback !== 'function') throw new Error('Wrong arguments');
      
      filePath = path.resolve(filePath);
      count = count || 0;
      var maxLimit = 5; // 5 * 500ms = 2,5s
      
      fs.readFile(filePath, opts, function(err, data) {
          if(err) {
              if(count >= maxLimit) callback(new Error('fsExt.readFie: max repeat limit reached').cause(err)); // repeat limit reached
              else setTimeout(function(){
                  readFile(filePath, opts, callback, count + 1);
              }, 500);
          }
          else callback(null, data);
      });
  }
docs: very simple read repeater, when gets error, try repeat after 500ms, but max 5 times
  @param {String} filePath
  @param {Function} callback(err, data)