This PR was merged into the 4.3-dev branch.Discussion----------[Mime] Add BodyRendererInterface| Q             | A| ------------- | ---| Branch?       | master| Bug fix?      | no| New feature?  | yes| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no <!-- don't forget to update UPGRADE-*.md and src/**/CHANGELOG.md files -->| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets | n/a| License       | MIT| Doc PR        | n/a<!--Write a short README entry for your feature/bugfix here (replace this comment block.)This will help people understand your PR and can be used as a start of the Doc PR.Additionally: - Bug fixes must be submitted against the lowest branch where they apply   (lowest branches are regularly merged to upper ones so they get the fixes too). - Features and deprecations must be submitted against the master branch.-->Commits-------0c9d684 [Mime] added BodyRendererInterface