Avoid useless vector coping by move semantic and using referenceness qualifier

[xDimon]

For example:

const std::vector<uint8_t> &BlaBla::toBuffer() const {
 return data_;
}

If we use it to make BlaBla and get std::vector<uint8_t> from that and that all.

std::vector<uint8_t> vec = BlaBla().toBuffer(); // <= copy here

Will be better to use ref-qualifier to move data from sigle-used temp object:

const std::vector<uint8_t> &BlaBla::toBuffer() const & { // <= method for case of usual object
 return data_;
 }
std::vector<uint8_t> BlaBla::toBuffer() const && { // <= method for case of temp object
 return std::move(data_);
}
std::vector<uint8_t> &BlaBla::asBuffer() { // <= method to access internal vector
 return data_;
}
const std::vector<uint8_t> &BlaBla::asBuffer() const { // <= method to RO-access internal vector
 return data_;
}