datasets_usage issue with api response

Using FreeNAS 11.3-U4.1, latest git clone of this module, it looks like the datasets_usage endpoints returns a gzip compressed output, and the http lib doesn't decompress it.

root@aubergine:/usr/lib/nagios/plugins/check_freenas# ./check_freenas.rb -s tofu -u root -p "aaaaaaa" -m datasets_usage -k -z smolpool
Traceback (most recent call last):
        5: from ./check_freenas.rb:429:in `<main>'
        4: from ./check_freenas.rb:429:in `new'
        3: from ./check_freenas.rb:122:in `initialize'
        2: from ./check_freenas.rb:306:in `dataset_usage_check'
        1: from /usr/lib/ruby/2.7.0/json/common.rb:156:in `parse'
/usr/lib/ruby/2.7.0/json/common.rb:156:in `parse': 783: unexpected token at '\x1F�\b' (JSON::ParserError)

Added a puts of @response.body and it's binary garbled stuff, if I |gunzip the check command, I see a json.

I wonder if the endpoint returns a range, the http lib seemingly doesn't decompress in that case.