post
https://messaging.api.eu1.scalar.zf.com/v1/messages/actions/send
Sends a message to a user using multipart/form-data. Required fields vary depending on contentType. For example:
content(string) is required only if contentType is 'text'.file(binary) is expected if contentType is 'image' or 'file'.
Supported for direct chat conversations (conversationType=chat).