Remove has_pending_responses_

src/connection.hpp

@@ -342,8 +342,6 @@ private:
                       // mutex_, but if non-empty mutex_ can be
                       // dropped while server accesses existing elements.
   int64_t outgoing_bytes_queued_{0}; // Counter of queued bytes
-  bool has_pending_responses_{
-      false}; // True if protocol handler has responses to process
   std::deque<PendingResponse>
       pending_response_queue_; // Responses awaiting protocol processing
   // Set to a negative number in `close`