let memoryCache = MemoryCache.default // or initialize

// Defining a string (or hash) key for a dog value.
let dogKey = StringKey<Dog>("dog")

// Setting a dog value in memoryCache.
memoryCache.set(dog, for: dogKey)

// Getting a cached dog value in memoryCache.
let cachedDog = try? memoryCache.value(for: dogKey)

// Removing a cached dog value in memoryCache.
memoryCache.remove(for: dogKey)

let dogKey = StringKey<Dog>("dog")

memoryCache.set(dog, for: dogKey)

let dog = try? memoryCache.value(for: dogKey)

memoryCache.remove(for: dogKey)

memoryCache.removeIfExpired(for: dogKey)

memoryCache.removeAll()

/// The maximum total cost that the memoryCache can hold before it starts evicting caches.
var totalCostLimit: Int

/// The maximum number of caches the memoryCache should hold.
var countLimit: Int

/// The total cost of values in the memoryCache.
var totalCost: Int

/// The number of values in the memoryCache.
var count: Int

/// A Boolean value indicating whether the memoryCache has no values.
var isEmpty: Bool

import MemoryCache

class SomeClass: NSObject, MemoryCacheDelegate {

    let memoryCache: MemoryCache
    
    init() {
        memoryCache = MemoryCache.default
        
        ...
        
        super.init()

        memoryCache.delegate = self
    }
    
    func memoryCache(_ memoryCache: MemoryCache, willEvict cache: Any) {
        // Called when an cache is about to be evicted or removed from the memoryCache.
    }
}

/// The expiration date is `.never`.
memoryCache.set(dog, for: dogKey, expiration: .never)

/// The expiration date is `.seconds("""10s""")`.
memoryCache.set(dog, for: dogKey, expiration: .seconds(10))

/// The expiration date is `.date("""TOMORROW""")`.
memoryCache.set(dog, for: dogKey, expiration: .date(Date().addingTimeInterval(60 * 60 * 24)))

/// Remove the cache of the specified key if it expired.
memoryCache.removeIfExpired(for: dogKey)