Plain Text Message
Description  | Plain messages are simplest of the message types and are supported by all channels.  | 
|---|
The body should be in JSON format and include the following properties:
Property  | Type  | Desc.  | 
|---|---|---|
type REQUIRED  | String  | Value = "PLAIN"  | 
markdownText OPTIONAL  | String  | Contains custom plain text message sent by end user.  | 
"body": {
        "type": "PLAIN",
        "markdownText": "Hi"
    }