OK. I trying with below example but I have got error.

import vibe.vibe;

void main()
	auto settings = new HTTPServerSettings;
	settings.port = 8080;
	settings.bindAddresses = ["::1", ""];
	settings.sessionStore = new MemorySessionStore;

	listenHTTP(settings, &hello);

	logInfo("Please open in your browser.");

void hello(HTTPServerRequest req, HTTPServerResponse res)
	int[] arr = [1, 2, 3, 4];

	auto session = res.startSession();
	session.set("array", arr);

	res.writeBody("Hello, World!");
vibe-session ~master: building configuration "application"...
/home/astar/.dub/packages/vibe-d-0.8.2-rc.1/vibe-d/http/vibe/http/session.d(92,3): Error: static assert  "Type int[] contains references, which is not supported for session storage."
source/app.d(21,13):        instantiated from here: set!(int[])
dmd failed with exit code 1.