在 LogDNA 中，我们有很多这样的行：
{"消息":"bend.eu-de.mybluemix.net - [2019-07-22T09:25:43.834+0000] \"POST /api/public/disco HTTP/1.1\" 200 91 1713 \"-\ " \"Apache-CXF/3.1.18\" \"10.100.29.195:37516\" \"160.00.23.107:61186\" x_forwarded_for:\"10.208.176.114,203.201.183.198, 20.105.29.195\" x_forwarded_proto:\ "https\" vcap_request_id:\"8800770-2007-4684-7791-ef5eab043c\" response_time:0.506587776 app_id:\"4736d7ea-f2c8-48b4-87e2-ce0cfaee40\" app_index:\"0\" x_global_transaction_id:\"067019e4003580"06a1726 " true_client_ip:\"-\" x_b3_traceid:\"0e360106751\" x_b3_spanid:\"0e0870106751\" x_b3_parentspanid:\"-\" b3:\"0e0006751-0e006751\"\n"}
是否可以在response_time上定义一个变量？我们可以在视图中使用这个变量吗？