Create an Email activity

*status* must be one of the following: - `inbox` to log an already received email. - `draft` to create a draft email. - `scheduled` to send an email at a scheduled date and time, which must be specified in the `date_scheduled` field. - `outbox` to actually **send** an email. To delay email sending by a few seconds (to allow undo), specify `send_in` in seconds (must be less than 60). - `sent` to log an already sent email. Only drafts can be modified, and their status can be changed to `scheduled` (to send later) or `outbox` (to send immediately). Scheduled emails, or emails in outbox that weren't sent yet can be canceled by setting the status back to `draft`. For scheduled, outbox, or sent emails, a `followup_date` may be posted, which will have Close create an email followup task if no response was received. We'll render an Email Template server-side if you include a `template_id` _without_ including `body_text` or `body_html` in your POST. To specify both a sender name and a sender email address when posting an email, you can use the `sender` field with the format `"sender": ""John Smith" <emailaddress@example.com>"` The `sender` field is **required** for emails with status `inbox`, `scheduled`, `outbox`, or `error`. It may be omitted for `draft` (since the sender can be specified later before sending) and `sent` (where it defaults to the email address of the `user` associated with the email or the owner of the API key). To include an attachment, you must first upload the file to Close using the [Files API](https://developer.close.com/api/resources/files). Then, add an object to the `attachments` array with the following fields: `url`, `filename`, `content_type`, and `size`. The `url` should be the URL provided in the `download.url` field of the response from the [Files API](https://developer.close.com/api/resources/files). It must begin `https://app.close.com/go/file/`.