Have you ever used the mutating modifier in your projects?

In Swift, the mutating modifier is used in methods of structures and enumerations to allow these methods to modify the properties of the instance. By default, structures and enumerations are value types, and their methods cannot modify properties without mutating.

Example of usage:

struct Counter {
    var count = 0
    mutating func increment() {
        count += 1
    }
}

var counter = Counter()
counter.increment()  // count is now 1

In my projects, I have used mutating for methods that need to change the state of structures, such as updating values or managing internal state without switching to classes.