nkostelnik/gulp-s3 — pull request #19 by fisch0920 (2014-06-24 15:50:29+00:00)
Title: Limit number of concurrent uploads via async.eachLimit

Limiting the number of concurrent uploads makes gulp-s3 much more robust in practice. I kept running into issues where either locally or remotely things would error out because gulp-s3 was creating the upload requests for all files back to back without capping the max number of concurrent uploads.