@Override
    public Promise<Boolean> exists(String path) {
        return adapter.toPromise(handler -> vertx.fileSystem().exists(path, handler));
    }
@ Override public Promise < Boolean > exists ( String path ) { return adapter . toPromise ( handler -> vertx . fileSystem ( ) . exists ( path , handler ) ) ; }
Determines whether the file as specified by the path {@code path} exists, asynchronously.

@param path path to the file
@return a promise for existence