Normally, when we pass an instance of a value type, such as a structure, a new copy of the instance is created. This means that if we have a large data structure that contains 100,000 elements, then every time we pass that instance we will have to copy all 100,000 elements. This can have a detrimental impact on the performance of our applications, especially if we pass the instance to numerous functions.
To solve this issue, Apple has implemented the copy-on-write feature for all the data structures (such as Array, Dictionary, and Set) in the Swift standard library. With copy-on-write, Swift does not make a second copy of the data structure until a change is made to that data structure. Therefore, if we pass an array of 50,000 elements to another part of our code, and that code does not make any changes to the array, we will avoid the runtime overhead of copying...