code: @Override
      public Promise<Void> chmodRecursive(String path, String perms, String dirPerms) {
          return adapter.toPromise(handler -> vertx.fileSystem().chmodRecursive(path, perms, dirPerms, handler));
      }
docs: Change the permissions on the file represented by {@code path} to {@code perms}, asynchronously.<p>
  The permission String takes the form rwxr-x--- as
  specified in {<a href="http://download.oracle.com/javase/7/docs/api/java/nio/file/attribute/PosixFilePermissions.html">here</a>}.
  <p>
  If the file is directory then all contents will also have their permissions changed recursively. Any directory permissions will
  be set to {@code dirPerms}, whilst any normal file permissions will be set to {@code perms}.
  
  @param path     the path to the file
  @param perms    the permissions string
  @param dirPerms the directory permissions
  @return a promise for completion