get:
  description: Get received messages count
  parameters:
    - name: sinceDate
      in: query
      description: Messages after this timestamp
      required: false
      schema:
        type: integer
    - name: unread
      in: query
      description: Retrieve only unread messages
      required: false
      schema:
        type: boolean
  responses:
    '200':
      description: message count response
      content:
        application/json:
          schema:
            type: object
            properties:
              count:
                type: integer