src/vs/workbench/services/extensions/common/rpcProtocol.ts/MessageIO/_requestJSONArgs
class MessageIO:	private static _requestJSONArgs(req: number, rpcId: number, method: string, args: string, usesCancellationToken: boolean): VSBuffer {
		const methodBuff = VSBuffer.fromString(method);
		const argsBuff = VSBuffer.fromString(args);

		let len = 0;
		len += MessageBuffer.sizeUInt8();
		len += MessageBuffer.sizeShortString(methodBuff);
		len += MessageBuffer.sizeLongString(argsBuff);

		const result = MessageBuffer.alloc(usesCancellationToken ? MessageType.RequestJSONArgsWithCancellation : MessageType.RequestJSONArgs, req, len);
		result.writeUInt8(rpcId);
		result.writeShortString(methodBuff);
		result.writeLongString(argsBuff);
		return result.buffer;
	}