Scheduled posts API on Mastodon seems a bit rough.

1. Post payload is a bit different than published posts (ScheduledStatus docs.joinmastodon.org/entities vs Status docs.joinmastodon.org/entities)
2. There's API to reschedule & delete but no edit docs.joinmastodon.org/methods/

Looking back at the initial PR (github.com/mastodon/mastodon/p): "The scheduled date must be at least 5 minutes into the future. At most, 300 toots can be scheduled at the same time. Only 50 toots can be scheduled for any given day."

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