Tell about the lifecycle of an object in iOS.

The lifecycle of an object in iOS is managed by the reference counting mechanism. The most common method is Automatic Reference Counting (ARC).

Lifecycle stages:

Creation: The object is created by initializing a class. The reference count is set to 1.
```
// Initializing an object of class MyClass
let myObject = MyClass() 
```

Usage: The object is used in the application. Other objects can hold references to it, increasing the reference count.

// Another object holds a reference
anotherObject.referenceToMyObject = myObject 
// The reference count of myObject increases

Deallocation: When the reference count of the object reaches zero, the runtime automatically calls the deinit() method (for Objective-C classes - dealloc). The object releases the occupied memory.
```
deinit {
    // Code to release resources
    print("Object deallocated")
}
```

Problems and solutions:

Retain Cycles (Strong reference cycles): Occur when two or more objects hold strong references to each other. The reference count of each object never reaches zero, and the objects are not deinitialized.
Solutions:
- Weak References: Marked with the weak keyword. Do not increase the reference count. Used for references to parent objects or delegates when the relationship is temporary or optional.
- Unowned References: Marked with the unowned keyword. Do not increase the reference count. Used when related objects always have the same lifecycle, and the reference is guaranteed not to be nil during use. If the object referenced by an unowned reference is deinitialized, accessing such a reference will lead to a runtime error.

Example of weak and unowned in closures to avoid strong reference cycles:

class Person {
    let name: String
    // Weak reference to closure to avoid cycle
    var greeting: (() -> Void)? 

    init(name: String) {
        self.name = name
        // Capture self as weak reference
        greeting = { [weak self] in 
            guard let self = self else { return }
            print("Hello, \(self.name)!")
        }
    }

    deinit {
        print("\(name) is being deinitialized")
    }
}

class Apartment {
    let unit: String
    // Weak reference to tenant
    weak var tenant: Person? 

    init(unit: String) {
        self.unit = unit
    }

    deinit {
        print("Apartment \(unit) is being deinitialized")
    }
}

Proper reference management is crucial to prevent memory leaks and maintain application stability.