Slice is NOT comparable
Standard library provide a way to compare 2 byte slices
Reference type such as pointers and channels, the == test whether two entities refer to the same thing
The only legal slice comparison is against nil
Zero value of slice is nil. Capacity of nil slice is 0. Not nil slice capacity may be 0 as well.
Use built-in append function to add element to a slice
It seems underlying array become another reference after slice capacity bigger than declared one
Append element to slice to exceed capacity, what will happen?
=> New slice will be generated
