StreamWrapper implementation

[dmitryuk]

Feature Request

Q	A
Flysystem Version	3.0.0

Scenario / Use-case

Then I worked on big package I've used https://github.com/twistor/flysystem-stream-wrapper package to create own scheme for flysystem package.
We need scheme because Symfony's FileValidator uses method is_file with string parameter to check file exiting. For example, fly://filename.txt working well.
After Flysystem migrate to v2 and then v3 Twistor package became abandoned. Another same package https://github.com/KnpLabs/Gaufrette also abandoned.
Now new package https://github.com/m2mtech/flysystem-stream-wrapper supports flysystem V3. In future it can be also abandoned and not supported well.
I think PhpLeague flysystem should have his own stream wrapper officially supported.

Can we implement it? Should it be a separate package or a part of this package?

[maxhelias]

Issue also requested on the symfony bundle : thephpleague/flysystem-bundle#96

[elazar]

I've written something that may serve this need: https://github.com/elazar/flystream