docs: add usage sample

[steveoh]

help folks know how to use this package.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
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[airbreather]

Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

Not required here, since this is just a README.md change.

Thank you for your contribution! Related: #56

[steveoh]

I never even looked at the wiki. Maybe the readme should link to the wiki as there are more complete examples for both packages there.