[Question]: When using io.CopyBuffer(), do you need to call Flush to send the data?

[KM-SF]

Actions I've taken before I'm here

• [X] I've thoroughly read the documentations about this problem but still have no answer.
• [X] I've searched the Github Issues/Discussions but didn't find any similar problems that have been solved.
• [X] I've searched the internet for this problem but didn't find anything helpful.

Questions with details

• 使用的v2.5.2的版本
• 服务端的使用默认的配置启动
• 场景：在简单的kv系统中，服务端接收到请求-> 处理完请求 -> 将结果发送回去这一个流程。
• 分析：我使用的是io.CopyBuffer(gnet.conn, RespReader)这个方式，将结果拷贝到gnet.conn中，但是这个方式好像不会发送数据到客户端，客户端用io.ReadFull会一直卡住，需要手动调用一次Flush才会发送数据。跟了一下代码，好像只是简单的把数据拷贝到buffer中。如果我直接调用Write的话，会发送数据到客户端
• 问题：如果使用io.CopyBuffer这个情况，是需要自己收到调用Flush是吗？

Code snippets (optional)

// Server：

func (s *Service) OnTraffic(c gnet.Conn) (action gnet.Action) {
    args = c.Context().(KVGetRequest)
    args.Decocde(c)

    go func(){
        respReader := KVGet(args)
        io.CopyBuffer(c,respReader,buff) // c.Write(resp) 这个方式不会卡住
        // c.Flush()  如果不手动flush，客户端会一直卡住
    }
}

// Client

func (c *Client) KVGet(req KVGetRequest) {
    c := net.Dial("tcp",p.Addr)
    c.Write(req.Bytes())
    io.ReadFull(conn,respBuf)
}

[panjf2000]

gnet.Conn 大部分的方法都不是并发安全的，不能放到新的 goroutine 里执行，仔细看文档：https://pkg.go.dev/github.com/panjf2000/gnet/v2#Conn

[gh-translator]

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Most methods of gnet.Conn are not concurrency-safe and cannot be executed in new goroutines. Read the documentation carefully: https://pkg.go.dev/github.com/panjf2000/gnet/v2#Conn