code: async def post_subscribe(request):
      
      args = await request.json()
      get_listener(request.app).subscribe(
          args['exchange'],
          args['routing']
      )
      return web.Response()
docs: ---
      tags:
      - Events
      summary: Subscribe to events.
      operationId: events.subscribe
      produces:
      - text/plain
      parameters:
      -
          in: body
          name: body
          description: Event message
          required: true
          schema:
              type: object
              properties:
                  exchange:
                      type: string
                  routing:
                      type: string