To use in CircuitPython, simply install the [Adafruit CircuitPython Bundle](https://circuitpython.org/libraries).
To use in CPython, `pip3 install adafruit-circuitpython-json-stream`. (It is modeled after the `json-stream` pypi package.)
Read the [docs](http://circuitpython.readthedocs.io/projects/json_stream/en/latest/) for info on how to use it.