Submit a campaign draft for sending. Only campaigns in 'draft' status can be sent; to send a campaign again, copy it and send the copy.
Supports both email and SMS campaigns. Behavior depends on the campaign's sending strategy:

• Immediate: Campaign will be sent immediately
• Scheduled: Campaign will be queued for the scheduled time with optional timezone optimization

Scopes:
campaigns.write

Rate Limiting:
This endpoint is rate limited to 400 requests per minute.