The Source Engine manages a relationship between file paths and their corresponding
integer-based source IDs. Additionally, it maintains the reverse - a map that traces
back from a source ID to its original file path. The primary objective of this
system is to enable clients that need to reference a file path to do so using an
integer-based ID. This numeric representation can be stored more efficiently as
a key in a hashmap.
The Source Engine is designed to be thread-safe. Its internal structures are
secured by the RwLock mechanism. This allows its functions to be invoked using
a straightforward non-mutable reference, ensuring safe concurrent access.