TCP close时，如果recvbuf中有数据，没有处理，不是正常FIN，而是RST，将丢失sendbuf里的数据

#include <iostream>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include <string.h>

using namespace std;

#define SERV_PORT 8888
#define BUF_SIZE 100000

int main(int argc, char *argv[])
{
    int listend;
    int backlog = 10; 
    struct sockaddr_in servaddr;
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(SERV_PORT);
    listend = socket(AF_INET, SOCK_STREAM, 0); 
    int check_ret = bind(listend, (struct sockaddr *)&servaddr, sizeof(servaddr));
    assert(check_ret>=0);
    check_ret = listen(listend, backlog);
    
    struct sockaddr_in addressclient;
    socklen_t clientlen = sizeof(addressclient);
   
    int connfd = accept(listend, (struct sockaddr *)&addressclient, &clientlen);
    assert(connfd>=0);
    cout<<"new conn com!"<<endl;
    sleep(10);

    char buf[BUF_SIZE];
    memset(buf, '0', BUF_SIZE);
    int w_count = write(connfd, buf, BUF_SIZE); 
    cout<<"write count:"<<w_count<<endl;    
    
    shutdown(connfd, SHUT_WR);
    char readbuf[BUF_SIZE];
    int res = 0;
    for(;;)
    {   
        res = read(connfd, readbuf, 200);
        if(!res)
        {   
            break;
        }   
    }   
    close(connfd);
    close(listend);
    return 0;
}