Speed up writing protobuf strings/bytes

[bdraco]

What does this implement/fix?

Speed up writing protobuf strings/bytes

I recently got an esp32 cam and noticed the performance was not so great over the api (https://community.home-assistant.io/t/getting-better-performance-from-an-espcam32/561615)

I tried a few different ways ... and this might be faster but not sure if its safe

    this->buffer_->resize(old_size + len);
    std::memcpy(&(*this->buffer_)[old_size], data, len);

so I settled on

this->buffer_->insert(this->buffer_->end(), data, data + len);

after reading https://stackoverflow.com/questions/2208293/what-is-the-most-efficient-way-to-append-one-stdvector-to-the-end-of-another , in theory it should be 2x the speed of the push_back but I currently have no way to validate that its actually faster on the ESP and not just locally.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Related issue or feature (if applicable): fixes

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

# Example config.yaml

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[jesserockz]

Seems like a very sensible change

[probot-esphome]

Hey there @OttoWinter, mind taking a look at this pull request as it has been labeled with an integration (api) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[bdraco]

thanks