Why is Xcode so slow to index or set breakpoint

Xcode is always indexing , when in this state, you can't edit anything when you set a breakpoint, it's take long time to resolve the vars value, it'a almost take 20 minutes

Macbook hardware: CPU: 2.6 GHz Intel Core i7 mem: 64 GB 2667 MHz DDR4

Why is Xcode so slow to index or set breakpoint
 
 
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