src/vs/workbench/services/extensions/common/rpcProtocol.ts/MessageIO/_serializeReplyOKJSON
class MessageIO:	private static _serializeReplyOKJSON(req: number, res: string): VSBuffer {
		const resBuff = VSBuffer.fromString(res);

		let len = 0;
		len += MessageBuffer.sizeLongString(resBuff);

		const result = MessageBuffer.alloc(MessageType.ReplyOKJSON, req, len);
		result.writeLongString(resBuff);
		return result.buffer;
	}