fn prepare_filesystem(
base_root: Arc<dyn FileSystem + Send + Sync>,
memory_limiter: Option<&DynFsMemoryLimiter>,
mounted_dirs: &[MountedDirectory],
container_mounts: Option<&BinaryPackageMounts>,
conflict_behavior: ExistingMountConflictBehavior,
) -> Result<WasiFsRoot, Error>