| Q               | A
| --------------- | ---
| Bug fix?        | no|yes
| New feature?    | no|yes
| BC breaks?      | no|yes
| Deprecations?   | no|yes
| Related tickets | fixes #X, partially #Y, mentioned in #Z
| Documentation   | if this is a new feature, link to pull request in https://github.com/php-http/documentation that adds relevant documentation
| License         | MIT


#### What's in this PR?

Explain what the changes in this PR do.


#### Why?

Which problem does the PR fix? (remove this section if you linked an issue above)


#### Example Usage

``` php
// If you added new features, show examples of how to use them here
// (remove this section if not a new feature)

$foo = new Foo();

// Now we can do
$foo->doSomething();
```


#### Checklist

- [ ] Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
- [ ] Documentation pull request created (if not simply a bugfix)


#### To Do

- [ ] If the PR is not complete but you want to discuss the approach, list what remains to be done here
