he trade-offs between in-line and out-of-line storage, including the performance implications of copying large structs.

The trade-offs between in-line and out-of-line storage, including the performance implications of copying large structs, are discussed in the session titled Explore Swift performance. Here are the key points:

1. Inline Storage:

   • Advantages: Avoids allocating memory on the heap, which is beneficial for small types.
   • Disadvantages: For larger types, the cost of copying can become significant. Copying a struct value means recursively copying all of its stored properties, which can lead to performance issues if there are many copies.

2. Out-of-Line Storage:

   • Advantages: Each copy refers to the same object, so memory is reused, which can be more efficient if the value is copied frequently.
   • Disadvantages: Typically used by class types, which have reference semantics. This means copying a class value involves copying the ownership of the reference, which just means retaining the object it refers to.

3. Performance Implications:

   • Copying Large Structs: When copying large structs, the cost comes in two parts. First, copying value types often involves more than just copying bits; it includes retaining object references. Second, each copy of the value needs its own storage for all stored properties, potentially using more memory.
   • Value Semantics vs. Reference Semantics: Swift encourages writing types with value semantics, where a copy of the value behaves independently from the original. Structs use inline storage and have value semantics, while classes use out-of-line storage and have reference semantics.

For a detailed explanation, you can refer to the session Explore Swift performance starting at 18:50.