lazy var iOSResumeDescription: String = { return “I am an iOS developer” }()

Here RHS is a closure call. The closure of type . ()-> Sting is called which returns a string.

lazy var iOSResumeDescription = “I am an iOS developer”

Here RHS is a string.

The whole point is that iOSResumeDescription will not be in memory until it is called for the first time. Forget about what is there in the RHS.