Optimize I/O performance

The asset importer reads large binary level files and the load time is a bottleneck. Rework the file I/O to reduce pauses: switch blocking fread loops to a buffered reader that reads in 4MB chunks, replace per-object file reads with a single pass that parses multiple objects into pre-sized vectors, and use std::ifstream::readsome or OS-level prefetch where available. Measure before and after with the provided perf harness and report wall time and peak memory.

Before I submit the I/O changes, make the optimization easy to sign off. Show a concise table with load times for representative levels, annotate hotspots in the parsing loop, explain why chunk sizes were chosen, and list any behavior changes (stream positioning, memory use). Highlight risky changes like turning synchronous reads into background threads and how to revert them quickly.

I moved reads to a background thread to avoid stalls. On one level run, a texture appears corrupted and the asset verifier logged a partial read. I suspect a race between loader and the main thread that consumes the asset. I cannot stop using background threads entirely. What is the most likely cause and the minimal synchronization or ordering change to ensure textures are fully available before use without undoing the performance gain?

Every project I touch we keep adding bespoke I/O optimizations that reduce one hitch then create another. I spend days firefighting level-specific load paths. What higher-level rule or architecture change should I adopt so bulk asset streaming is reliable across levels and teams without constant per-level rework?