Chrome Timeline的指标说明：Blocked、Connect、Send、Wait、Receive
Blocked time includes any pre-processing time (such as cache lookup) and the time spent waiting for a network connection to become available. Internet Explorer will only create a maximum of two concurrent network connections per host name (i.e. www.microsoft.com) and will queue up requests until a network connection is available. Often the Blocked time is the most significant factor in the download time of images embedded in a web page.
阻塞时间，包括所有的过程之前的时间（像，cache对比）和等待网络链接的时间，IE在每个主机名（像 http://www.microsoft.com/）下最多只创建两个当前的网络连接，而且要排队等待直到这个网络链接可用，通常，闭塞时间影响网页中图片加载时间的重要因素。
Connect is the time required to create a TCP connection to the web server (or proxy). If a secure HTTPS connection 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.
连接时间，是创建TCP连接到服务器或者代理服务器所花费的时间，如果一个包含SSL的安全的HTTPS连接存在，Keep-Alive链接经常被用到，以避免多次重复的连接WEB服务器。
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
发送，是发送HTTP请求到服务器的时间，而且这个时间取决与发送请求的数据量的大小，例如，长的发送时间是由于用 PSOT方式上传文件造成的。
Wait is the idle time spent waiting for a response message from the server. This value includes delays introduced 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 size of the content returned, network bandwidth and whether HTTP compression was used.
接收，是花费在从服务器读取响应消息的时间。这个值可以受到请求消息内容的大小，网络带宽和是否使用了HTTP压缩。
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 and the time taken to get the first byte of the response message.
TTFB，是最初的网络请求被发起到从服务器接收到第一个字节这段时间，它包含了TCP连接时间，发送HTTP请求时间和获得响应消息第一个字节的时间。
Network is the total duration of all network related operations for an HTTP request.
Network，是所有的对一个HTTP请求的相关操作的这段时间。