I'm happy to see that requester-pays support was just added!

afaict, I can't set the userProject in a CloudStorageFileSystemProvider that gets instantiated via the Java NIO FileSystemProvider machinery, which uses Class.newInstance() to invoke the nullary constructor:

import java.net.URI;
import java.nio.file.Paths;
import java.nio.file.Files;
Files.newDirectoryStream(Paths.get(new URI("gs://<bucket>")))

throws:

com.google.cloud.storage.StorageException: Bucket is requester pays bucket but no user project provided.
  at com.google.cloud.storage.spi.v1.HttpStorageRpc.translate(HttpStorageRpc.java:220)
  at com.google.cloud.storage.spi.v1.HttpStorageRpc.list(HttpStorageRpc.java:347)
  at com.google.cloud.storage.StorageImpl$8.call(StorageImpl.java:299)
  …

Is there a way to set the user-project, other than as a ctor param?

• an environment variable would seem easiest
  • afaict there's no standard mechanism for doing that across GCS libraries in various languages
  • perhaps it's still ok to add one here
• a setter would help a bit
  • I'll be mainly using it from hammerlab/path-utils, where I (unfortunately) have code to reach into the installedProviders and modify the providers for a given URI scheme
  • a setter would at least save me from a second reflection hack to reach