parts array.
Part types
A Message has 1 to 100 parts. A
link must be the only part in its Message.
Send paths
Message lifecycle
Next steps
Sending Messages
Send text and multipart content.
Attachments
Upload and reuse files.
Voice memos
Send native audio messages.
Rich link previews
Send a URL as a link part.
Mentions
Address a Contact in a group.
Replies
Reply to an exact part.
Reactions
Add standard or custom reactions.
Message details
Read status, timestamps, and history.