Function resolve_cache_dir 

pub fn resolve_cache_dir() -> Utf8PathBuf

Resolves the binary cache directory from environment and XDG conventions.

The resolution order is:

1. PG_BINARY_CACHE_DIR environment variable if set and valid UTF-8
2. $XDG_CACHE_HOME/pg-embedded/binaries if XDG_CACHE_HOME is set
3. ~/.cache/pg-embedded/binaries as fallback
4. std::env::temp_dir()/pg-embedded/binaries as last resort (platform-dependent)

Examples

use pg_embedded_setup_unpriv::cache::resolve_cache_dir;

let cache_dir = resolve_cache_dir();
assert!(!cache_dir.as_str().is_empty());