anchor.diff:  
   -spec send_heartbeat(#state{}) -> #state{}.
   send_heartbeat(#state{command_sock = Sock,
  -                      client_name = ClientName,
                         org_name = OrgName,
                         sequence = Sequence,
                         session_key = SessionKey,
  
positive.code: -record(state,
          {command_sock :: any(),
           heartbeat_sock :: any(),
           client_name :: binary(),
           org_name :: binary(),
           heartbeat_interval :: integer(),
           sequence :: integer(),
  
negative.code: 
      State = #state{command_sock = CommandSock,
                     heartbeat_sock = HeartbeatSock,
                     org_name = OrgName,
                     heartbeat_interval = Interval,
                     sequence = 0,
  