IMessageOptions interface 
Optional message properties that can be sent to things like prompts or session.say().
Properties
| attachment | Hint for how clients should layout multiple attachments. The default value is 'list'. | 
| attachments | For incoming messages contains attachments like images sent from the user. For outgoing messages contains objects like cards or images to send to the user. | 
| entities | Structured objects passed to the bot or user. | 
| input | Hint for clients letting them know if the bot is expecting further input or not. The built-in prompts will automatically populate this value for outgoing messages. | 
| text | Format of text fields. The default value is 'markdown'. | 
Property Details
		attachmentLayout
	 
	Hint for how clients should layout multiple attachments. The default value is 'list'.
attachmentLayout?: stringProperty Value
string
attachments
For incoming messages contains attachments like images sent from the user. For outgoing messages contains objects like cards or images to send to the user.
attachments?: IAttachment[]Property Value
entities
Structured objects passed to the bot or user.
entities?: any[]Property Value
any[]
		inputHint
	 
	Hint for clients letting them know if the bot is expecting further input or not. The built-in prompts will automatically populate this value for outgoing messages.
inputHint?: stringProperty Value
string
		textFormat
	 
	Format of text fields. The default value is 'markdown'.
textFormat?: stringProperty Value
string