{"HTTP/1.1", "Host: {\r\n", 400},
		{"HTTP/1.1", "Host: }\r\n", 400},
		{"HTTP/1.1", "Host: first\r\nHost: second\r\n", 400},

		// HTTP/1.0 can lack a host header, but if present
		// must play by the rules too:
		{"HTTP/1.0", "", 200},
		{"HTTP/1.0", "Host: first\r\nHost: second\r\n", 400},
		{"HTTP/1.0", "Host: \xff\r\n", 400},

		// Make an exception for HTTP upgrade requests:
		{"PRI * HTTP/2.0", "", 200},