private int getByteCountFromFirstUtf8Byte(byte firstByte) {
        if ((firstByte & 0b10000000) == 0) {
            return 1;
        } else if ((firstByte & 0b11100000) == 0b11000000) {
            return 2;
        } else if ((firstByte & 0b11110000) == 0b11100000) {
            return 3;
        } else if ((firstByte & 0b11111000) == 0b11110000) {
            return 4;
        }
        return 0;
    }
@return 0 if it is not the first byte of a UTF character
turms-server-common/src/main/java/im/turms/server/common/infra/lang/Utf8String.java