gistfile1.scala

    val dataBuilder = StringBuilder.newBuilder

    session.bufferOption match {
      case Some(buffer) =>
        dataBuilder ++= buffer.result().mkString
        buffer.clear()
      case _ =>
    }
    
    o match {
      case str: String =>
        dataBuilder ++= str
      case buf: ByteBuffer =>
        dataBuilder ++= (charset decode buf).toString
    }