Does the 'let' keyword ensure safety when working concurrently from multiple threads?

The keyword let in Swift is used to declare constants — values that cannot be changed after initialization. However, let does not provide thread safety.

Thread safety depends on how data is used and synchronized between threads. Even if a variable is declared with let, if it references a mutable object (for example, a class), the internal state of that object can change, which can lead to issues with concurrent access.

To ensure safety when working with multithreading, mechanisms such as synchronization (e.g., DispatchQueue, NSLock, atomic operations) should be used, or immutable data structures should be employed, which guarantee that the state does not change after creation.