src/vs/workbench/api/common/extHostExtensionService.ts/AbstractExtHostExtensionService/$test_down
class AbstractExtHostExtensionService:	public async $test_down(size: number): Promise<VSBuffer> {
		let buff = VSBuffer.alloc(size);
		let value = Math.random() % 256;
		for (let i = 0; i < size; i++) {
			buff.writeUInt8(value, i);
		}
		return buff;
	}