def subscribe *args, &block
         raise "WebSocket / SSE connection missing" unless _pl__client
         if(block)
            _pl__client.subscribe *args, &block
         else
            _pl__client.subscribe *args
         end
      end
def subscribe *args, &block
         raise "WebSocket / SSE connection missing" unless _pl__client
         if(block)
            _pl__client.subscribe *args, &block
         else
            _pl__client.subscribe *args
         end
      end
Subscribes to a Pub/Sub stream / channel or replaces an existing subscription to the same stream / channel (raises an error unless an SSE / WebSocket connection was established).