         lines = str.split('\n')
 
       if not lines? or lines.length == 0
-        remainder = concat(remainder, newRemainder)
+        remainder = remainder + newRemainder
       else
-        lines[0] = remainder + lines[0] if remainder?
+        lines[0] = remainder + lines[0] if remainder
         callback(lines, line)
         remainder = newRemainder
 

        lines = null
      else if index > -1 and index == bytesRead - 1
        # the last char is a newline
        newRemainder = null
        str = chunkedBuffer.toString("utf8", 0, bytesRead - 1)
        lines = str.split('\n')
      else

  fd = fs.openSync(path, "r");
  try
    offset = 0
    remainder = ''
    return if isBinaryFile(headerBuffer, fs.readSync(fd, headerBuffer, 0, 256))

    chunkedBuffer ?= new Buffer(chunkSize)
