Proposal to allow files to pass through `dest` without writing them to disk.

@jonschlinkert and I have been trying to figure out a way to pipe files through dest but not actually write the files to disk or create the directories.

The goal is to ensure the file properties are updated using the same logic from prepare-write, then use the properties in another stream plugin. Our specific use case is to create a directory tree from the destination file paths.

We’ve come up with this solution, which uses a file.writeFile property to skip creating the destination directory and return early in write-contents when set to false.

Will you accept a pull request with this change, or suggest another way we could accomplish the same thing?

Thanks.

[phated]

Interesting side note that I didn’t want to type on my phone last night: in refactoring the tests, I’ve found a lot of inconsistencies with the prepareWrite module and would like to have it fully unit tested apart from gulp.dest. So this issue comes at an opportune time. We also want to reach parity with the gulp.src method (ref #191) so a module could expose a src/dest prepare stream. As soon as I finish this test refactor, I’ll look into splitting it apart.

[phated]

Due to this always being a Transform stream, the tests will have to always use from and to or concat. The reason vinyl-fs sinks is due to a bad pattern we support (sometimes a Transform stream/sometimes a writeable)