Guzzle with logger

services.yml

services:
    guzzle.client:
        class: Guzzle\Http\Client
        calls:
            - [addSubscriber, ["@guzzle.logger"]]

    guzzle.logger:
        class: Guzzle\Log\MonologLogAdapter
        arguments:
            - "@logger"
        tags:
            - { name: monolog.logger, channel: api }