Color-code resource types in Chrome development tool

This option is available in Chrome development tool – Settings – General:

If it is switched off:

If switched on, when you hover the mouse to the given row in Network tab, the duration of two types of time used, Waiting and Content Download, will be displayed automatically.

And if you put the mouse under column “Timeline – Start Time” and wait for a second, the detailed timing information of this network request will be displayed.