couchdb-php | PHP package to interact with CouchDB using Memcached | Database library

I am writing a php script to interact with a CouchDb server. The script reads an SQL database and creates documents and PUTs them on the server. Each script runs every 5 minutes and puts about 2000 documents (creates and updates).

Running sync, this takes about 3 minutes to PUT all the docs. In a test I did using node and promises, I found CouchDb can handle 100 asnyc puts at the same time and respond back in only slightly more time than it took to do a single document. I want to utilize this feature in PHP instead.
I have available, php 5.3 and php 7.0.10 on a Windows server.

How do I do this asnyc?

My first thought was using the pclose(popen()) trick, but that spawns a new process each time, and even if I restrict this to 100 docs at a time (my tests show up to 700 at a time is doable), that would still results in 6 scripts creating and recreating total of 600 new processes every 100/2000 docs every 5 minutes, or a total of 12,000 processes created and run every 5 minutes. I don't think Windows can handle that.

My second idea was to set up a basic node script to handle it, with PHP creating and formatting the data, writing to a file, and passing the file to a node script to process async and report back to PHP using exec. But I am hoping to find a pure PHP solution.

I currently send requests to couch like this