vinyl-ftp does not upload the exists folder

Question

My code:

var conn = ftp.create(config['tmt_preview']);
gulp.src('./dist/**/*.*', {base: '.', buffer: false})
   .pipe(conn.newerOrDifferentSize('/project'))
   .pipe(conn.dest('/project'));

Console outputs:

[15:40:04] Starting 'tmt_preview'...
[15:40:04] Finished 'tmt_preview' after 395 ms                 

First run everything is ok, take some change, run gulp ftp again, and you can see: the process not exit, and remotePath can not reflush. May i make anything wrong?