Add static method to create new Stream and allow instant chaining

[barteksc]

[bertptrs]

Hi, first of all, thank you for contributing to this project.

I currently cannot accept your pull request, as the project has rotten a bit over the last two years, and I needed to fix some stuff. So, could you please:

1. Rebase from the current master branch, so that the CI can do its job, and
2. Please only submit one feature per pull request. Your second commit is completely unrelated to the first one

If you edit your PR, I'd be happy to include it.

[barteksc]

Hi,

I've rebased from current master, but my problem is that I'm struggling with legacy project running on PHP 5.6. I see that you've changed minimum PHP version in composer.json to 7.0. Is it possible to return to 5.5? If not, I can still use your project with --ignore-platform-reqs.

I will create separated PRs on feature branches.

Thanks, Bartek

[bertptrs]

Sorry for taking a long time to respond. The reason I've bumped the minimum PHP version is because tools like PHPunit are no longer supported on those PHP versions, and PHPunit 6.x requires PHP 7 or higher.

However, I think that I can remove the parts of the actual library that need PHP 7 and restore backwards compatibility. PHPunit 5 and PHPunit 6 are not compatible, so running tests would be a little harder. I think it would be fine to only test on modern versions (which PHP 7 isn't anymore, since it's been EOL for some time now) and keep track of BC breaks manually.

Please note that the code you added currently breaks the style guide, and cannot be accepted as-is. Please reformat it or allow php-cs-fixer to fix it. Then I will be able to accept your PR.