code: 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
docs: 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).