toImmutable

Converts the current PersistentDataContainer instance to an immutable implementation.

This method creates a specialized immutable representation of the container, depending on its size and structure:

• Returns EmptyPersistentDataContainer if the container is empty.

• Creates a SingletonPersistentDataContainer if the container contains exactly one key-value pair.

• Constructs a PersistentDataContainerImpl for containers with more than one key-value pair.

Note: This operation ensures the resulting container is immutable, preventing further modifications.