Storing binary data buffer in protocol buffer message

I have a binary data buffer which i want to store in a protocol buffer.

In the documentation (https://developers.google.com/protocol-buffers/docs/proto#scalar) it says that the bytes type is equivalent to string in C++. I could not believe this so i had to try it and yes, this seems to be the case..

This proto:

message BufferMsg {
  required bytes buffer = 1;
}

gives a message definition containing this:

private:
  ::std::string* buffer_;

The public setter/getter API looks like this:

  // required bytes buffer = 1;
  inline bool has_buffer() const;
  inline void clear_buffer();
  static const int kBufferFieldNumber = 1;
  inline const ::std::string& buffer() const;
  inline void set_buffer(const ::std::string& value);
  inline void set_buffer(const char* value);
  inline void set_buffer(const void* value, size_t size);
  inline ::std::string* mutable_buffer();
  inline ::std::string* release_buffer();
  inline void set_allocated_buffer(::std::string* buffer);

Surely, this cannot be the way to store binary data in a message. How should it be done? In C++ i would typically use an unsigned char array or something like that to store the data.

Copyright Notice：Content Author:「Martin G」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/42645047/storing-binary-data-buffer-in-protocol-buffer-message