How to use

retain

method

in

io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame

  @Override
  protected void decode(ChannelHandlerContext ctx, BinaryWebSocketFrame msg, List<Object> out) throws Exception {
    out.add(msg.retain().content());
  }
}

  @Override
  protected void encode(ChannelHandlerContext ctx, ByteBuf msg, List<Object> out) {
    out.add(new BinaryWebSocketFrame(msg).retain());
  }
}