iOS-关于网络性能监控的总结

• NSURLSessionTaskTransactionMetrics
  An object that encapsualtes the performance metrics collected by the URL Loading System during the execution of a session task.
  用于封装在执行会话任务期间URL加载系统收集的性能指标。
  Apple官方文档参考

• Timeline of temporal metrics for a URL session task
  URL会话任务的时间指标时间轴

  
  
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• fetchStartDate
  The time when the task started fetching the resource, from the server or locally.

• domainLookupStartDate
  The time immediately before the task started the name lookup for the resource.

• domainLookupEndDate
  The time after the name lookup was completed.

• connectStartDate
  The time immediately before the task started establishing a TCP connection to the server.

• secureConnectionStartDate
  The time immediately before the task started the TLS security handshake to secure the current connection.

• secureConnectionEndDate
  The time immediately after the security handshake completed.

• connectEndDate
  The time immediately after the task finished establishing the connection to the server.

• requestStartDate
  The time immediately before the task started requesting the resource, regardless of whether it is retrieved from the server or local resources.

• requestEndDate
  The time immediately after the task finished requesting the resource, regardless of whether it was retrieved from the server or local resources.

• responseStartDate
  The time immediately after the task received the first byte of the response from the server or from local resources.

• responseEndDate
  The time immediately after the task received the last byte of the resource.