Blocked time includes any pre-processing time (such as cache lookup) and the time spent waiting for a netw
ork connection to become available. Internet Explorer will only create a maximum of two concurrent netw
ork connections per host name (i.e. www.microsoft.com) and will queue up requests until a network connec
tion is available. Often the Blocked time is the most significant factor in the download time of images embed
ded in a web page.
Connect is the time required to create a TCP connection to the web server (or proxy). If a secure HTTPS co
nnection is being used this time includes the SSL handshake process. Keep-Alive connections are often used
to avoid the overhead of repeatedly connecting to the web server.
Send is the time required to send the HTTP request message to the server and will depend on the amount
of data that is sent to the server. For example, long Send times will result from uploading files using an HTTP
POST
Wait is the idle time spent waiting for a response message from the server. This value includes delays introd
uced due to network latency and the time required to process the request on the web server.
等待，是花费在等待服务器响应消息的空闲时间，这个值包括网络延迟和服务器处理请求的时间。
Receive is the time taken to read the response message from the server. This value will be depend on the siz
e of the content returned, network bandwidth and whether HTTP compression was used.
Cache Read is the time taken to read the content from the browser cache during (Cache) or 304 responses.
缓存读取，是花费在从浏览器缓存中读取内容或者304响应的时间。
TTFB (or Time To First Byte) is the duration from the initial network request being initiated by the browser to
the first byte being received from the server. It includes TCP connection time, the time to send the request a
nd the time taken to get the first byte of the response message.