# Open an asset using it's name and returning a NativeAssetFileDescriptor
	# `file_name` is
	private fun open_fd(file_name: String): NativeAssetFileDescriptor do
		sys.jni_env.push_local_frame(2)
		var return_value = native_assets_manager.open_fd(file_name.to_java_string).new_global_ref
		sys.jni_env.pop_local_frame
		return return_value
	end