installDefaultSpzInflater

Install the platform-default SpzInflater on SpzGaussianLoader.inflater when the slot is empty. Idempotent. No-op on platforms without a built-in gzip; apps targeting those must wire their own SpzInflater before the first SPZ tile is fetched.

Kotlin/Native has no built-in gzip — leave SpzGaussianLoader.inflater unset. Apps that need SPZ on iOS register a compression-framework backed SpzInflater before fetching the first SPZ tile.

JVM + Android default: GZIPInputStream-backed JvmSpzInflater.

Browser targets (js + wasmJs) have no synchronous gzip primitive — CompressionStream is async-only. Leave SpzGaussianLoader.inflater unset; apps that need SPZ in the browser register a pako-binding-backed SpzInflater before fetching the first SPZ tile.