ChangeArrayIndexByReference - Slices/Arrays are contiguous memory addresses, which means you can get the reference(address) of on of the indexes, and change its content.

MapExample - Different from another data structures, maps and channels in Golang are automatically created as pointers under the hood, so that is why when you send a map through another function, if you change it, the original one will be also changed.

SliceNotPassByReference - When you send a slice do another function, it doesn't pass by reference, Golang don't pass by reference, so if you change the copy of the slice inside the called function, the original slice will remain untouched.

SlicePassByReferenceAddress - Here we are going to send the reference address of the slice, and change its content, and as we can see, the original slice will be changed.

SafeCounter is safe to use concurrently.