On my Steam Deck, this reduces the time it takes to initialize the wg_parser radically (by around 1 second). This helps in the game WILD HEARTS, which doesn't present while loading help videos during gameplay, causing large stutters.
Because GStreamer can randomly access the file with no known pattern on our side, I opted to implement this by buffering 4 chunks so that interleaved reads to different areas of the file don't cause us to discard and reload cached data more than we need to.