It would be nice to have the tweet button as a ds field.
Patch attached with a simple integration.
Although it's not used at present it's better to pass in entity and entity_type to the theme function. New patch attached.
@jonhattan - I'd still like to get this in but the patch didn't apply cleanly and I didn't really have time to fully test / tweak. So kinda assumed after 4 years marking as outdated was the best approach.
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