Lateinit.swift

@propertyWrapper
struct Lateinit<T> {
  private var _value: T?
  
  var wrappedValue: T {
    get { 
      guard let value = _value else {
        fatalError("Property being accessed without initialization")
      }
      return value
    }
    set { 
      guard _value == nil else {
        fatalError("Property already initialized")
      }
      _value = newValue
    }
  }
}

// Now we can declate non-optional variable without initialization
@Lateinit var name: String

// This is going to crash
print(name)

//So, firstly, we need to initialize it
name = "Swift"
print(name)

//Also, we can't change property after initialization
name = "Another one" //This is forbidden and going to crash