anchor.diff:  %%   been prepared, nothing happens.
   %%
   %% @spec unprepare(Name::atom()) -> ok
  -unprepare(Name) ->
  -    gen_server:cast(?SERVER, {unprepare, Name}).
  +unprepare(ServerName, Name) ->
  +    gen_server:cast(ServerName, {unprepare, Name}).
   
   %% @doc Get the prepared statement with the given name.
   %%
  
positive.code: %%    User::string(), Password::string(), Database::string(),
  %%    Encoding::string(), Reconnect::bool(), LinkConnection::bool()) ->
  %%      {ok, ConnPid} | {error, Reason}
  connect(PoolId, Host, Port, User, Password, Database, Encoding, Reconnect,
         LinkConnection) ->
      Port1 = if Port == undefined -> ?PORT; true -> Port end,
      Fun = if LinkConnection ->
  
negative.code: 	    {reply, {error, {no_connection_in_pool, PoolId}}, State}
      end.
  
  call_server(ServerName, Msg, Timeout) ->
  	%%修改第三个参数Timeout 为，增加超时时间设置(默认超时时间为5秒)
  	Timeout1 = 20000,
      if Timeout == undefined ->
  	    gen_server:call(ServerName, Msg, Timeout1);
         true ->
  	    gen_server:call(ServerName, Msg, Timeout1)
      end.
  
  add_conn(Conn, State) ->
  