google协议缓冲区编码字符串

我有一个使用协议缓冲区的代码片段,但是writeTo方法中的字符串值没有编码

在编写输出流之后,我可以读取字符串值

business::Company company;
company.set_name("Example Ltd.");
company.set_url("http://www.example.com");

 // 1st employee
 {
   business::Employee *employee = company.add_employee();
   employee->set_first_name("John");
   employee->set_last_name("Doe");
   employee->set_email("john.doe@example.com");
 }           

fstream output("company.bin", ios::out | ios::trunc | ios::binary);
company.SerializeToOstream(&output);