I am trying to write my own mysql client.but I send data to server always receive: “packets out of or …”

I have been resolve server info and are successfully.

env:
mysql 8.0.32
Protocol::HandshakeV10

this is my code:

unsigned char stage0[SHA256_DIGEST_LENGTH];
unsigned char stage1[SHA256_DIGEST_LENGTH];
unsigned char stage2[SHA256_DIGEST_LENGTH];
unsigned char stage3[SHA256_DIGEST_LENGTH];
unsigned char stageAll[SHA256_DIGEST_LENGTH];

if (strcmp(MySQLServInfo.MySQLServInfoData.AuthPluginName.c_str(), MySQLPluginName.cachingSha2Password) == 0) {
// using caching_sha2_password
// XOR(SHA256(password), SHA256(SHA256(SHA256(password)), Nonce))
// globalVar.MySQL_Password is string, is mysql password.
        // first sha256 -> SHA256(password) general sha256 digest.
        SHA256((const unsigned char*) globalVar.MySQL_Password.c_str(), strlen(globalVar.MySQL_Password.c_str()), stage0);

        // second sha256 inner -> SHA256(password)
        SHA256((const unsigned char*) globalVar.MySQL_Password.c_str(), strlen(globalVar.MySQL_Password.c_str()), stage1);
        // SHA256(SHA256(password))
        SHA256((const unsigned char*) stage1, sizeof(stage1)/sizeof(stage1[0]), stage2);
        // stage2 + nonce
        // MySQLServInfo.MySQLServInfoData.ServerAuthDataPart: client recived 
exchange number.contain tow part.length: 8(one of part) + 12(two of part).
        for (int i = 0; i < SHA256_DIGEST_LENGTH; ++i) {
            MySQLServInfo.MySQLServInfoData.ServerAuthDataPart += stage2[i];
        }
        // SHA256(SHA256(SHA256(password)), Nonce)
        SHA256((const unsigned char*)MySQLServInfo.MySQLServInfoData.ServerAuthDataPart.c_str(), strlen(MySQLServInfo.MySQLServInfoData.ServerAuthDataPart.c_str()), stage3);
        // stage0 ^ stage3 -> XOR(SHA256(password), SHA256(SHA256(SHA256(password)), Nonce)) 
        for (int i = 0; i < SHA256_DIGEST_LENGTH; ++i) {
            stageAll[i] = stage0[i] ^ stage3[i];
        }
    } else if (strcmp(MySQLServInfo.MySQLServInfoData.AuthPluginName.c_str(), MySQLPluginName.mysqlNativePassword) == 0) {
        // sha1
        ...
    } else {
        printf("unknown auth plugin: %s", MySQLServInfo.MySQLServInfoData.AuthPluginName.c_str());
        return 0;
    }
    // CapabilityFlags1
    
    // length of stage3
    const int authRespLen = sizeof(stage3);
    uint8_t authRespLEIBuf[9];
    // return authRespLEI = 32. SHA256_DIGEST_LENGTH's length
    uint8_t* authRespLEI = appendLengthEncodedInteger(authRespLEIBuf, authRespLen);

    // send data length
    const int pktLen = 4 + 4 + 4 + 1 + 23 + strlen(MySQLClientSendInfo.MySQLClientSendInfoData.UserName.c_str()) + 1 + 33 +
                       strlen(MySQLClientSendInfo.MySQLClientSendInfoData.DataBaseName.c_str()) + 1 + strlen(MySQLClientSendInfo.MySQLClientSendInfoData.ClientPluginName.c_str()) + 1;
    uint8_t data[pktLen];
    // From mysql source code: CLIENT_BASIC_FLAGS, define:
    // #define CLIENT_BASIC_FLAGS                                          
    // (CLIENT_ALL_FLAGS &                                               
    // ~(CLIENT_SSL | CLIENT_COMPRESS | CLIENT_SSL_VERIFY_SERVER_CERT | 
    // CLIENT_ZSTD_COMPRESSION_ALGORITHM))
    MySQLClientSendInfo.MySQLClientSendInfoData.CapabilityFlagsAll = CLIENT_BASIC_FLAGS;

    int position = 0;
    for(int i = 0; i < 3; i++){
        data[position] = (pktLen-4 >> (i * 8)) & 0b11111111;
        position += 1;
    }
    data[position] = 1;
    position += 1; // 4
    data[position] = MySQLClientSendInfo.MySQLClientSendInfoData.CapabilityFlagsAll;
    position += 1;
    data[position] = 0x00;
    position += 1;
    data[position] = 0x00;
    position += 1;
    data[position] = 0x00;
    position += 1;
    // max packet length
    data[position] = pktLen;
    position += 1;
    data[position] = 0x00;
    position += 1;
    data[position] = 0x00;
    position += 1;
    data[position] = 0x00;
    position += 1;
    // character set
    for (int i = 0; i < 23; ++i) {
        data[position] = MySQLClientSendInfo.MySQLClientSendInfoData.Filler[i];
        position += 1;
    }
    // username 
    for(int i = 0; i < strlen(MySQLClientSendInfo.MySQLClientSendInfoData.UserName.c_str()) + 1; i++) {
        data[position] = MySQLClientSendInfo.MySQLClientSendInfoData.UserName[i];
        position += 1;
    }

    data[position] = authRespLEI; // stageAll length 32
    position += 1;
    // append to data
    for (int i = 0; i < SHA256_DIGEST_LENGTH; ++i) {
        data[position] = stageAll[i];
        position += 1;
    }

    // database name
    for(int i = 0; i < strlen(MySQLClientSendInfo.MySQLClientSendInfoData.DataBaseName.c_str()) + 1; i++) {
        data[position] = MySQLClientSendInfo.MySQLClientSendInfoData.DataBaseName[i];
        position += 1;
    }

    // plugin name: caching_sha2_password
    for(int i = 0; i < strlen(MySQLClientSendInfo.MySQLClientSendInfoData.ClientPluginName.c_str()) + 1; i++) {
        data[position] = MySQLClientSendInfo.MySQLClientSendInfoData.ClientPluginName[i];
        position += 1;
    }
    int len = send(fd, data, sizeof(data)/sizeof(data[0]), 0);

thank you for reply me.

all format in Protocol::HandshakeV10.i can not recv correct message.