The diffusion.py program is a toy simulation of Brownian motion on the integer
line to simulate diffusion. Each task flips a coin a given number of times; if
0 move left, if 1 move right.

To run:

1. Install CCTools. For example, using conda:
conda create --yes --name work_queue_env python=3.8
conda install --yes --name work_queue_env install --channel=conda-forge ndcctools
conda activate work_queue_env

2. Execute (for 500 tasks, 100 steps each): python wq_diffusion.py 500 100
3. Start workers, such as: work_queue_worker localhost 9123

This example assumes that the worker is executed inside a valid python
environment. (For example, that the conda environment work_queue_env or similar
is available at the worker's execution site.)