@Override
  public FileSystem newFileSystem(Path path, Map<String, ?> env) throws IOException {
    FileSystemProvider realProvider = path.getFileSystem().provider();
    return realProvider.newFileSystem(path, env);
  }
Invokes the {@code toPath(URI)} method on the given {@code FileSystem}.
jimfs/src/main/java/com/google/common/jimfs/SystemJimfsFileSystemProvider.java