Add handling for "message of the day"

[ewanas]

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Code Review Checklist (to be filled out by reviewer)

• Description accurately reflects what changes are being made.
• Description explains why the changes are being made (or references an issue containing one).
• The PR appropriately sized.
• New code has enough tests.
• New code has enough documentation to answer "how do I use it?" and "what does it do?".
• Existing documentation is up-to-date, if impacted.

[meejah]

I haven't looked at this Go codebase in very much detail, so maybe not the best reviewer ... but there's not tests, does this repo not have unit tests, or ...?

[ewanas]

I haven't looked at this Go codebase in very much detail, so maybe not the best reviewer ... but there's not tests, does this repo not have unit tests, or ...?

C bindings don't have tests yet, but I will add tests for the Go changes.