return fmt.Errorf(`invalid header %q: header cannot have ":" prefix`, name)
	}
	return nil
}

// Copy from https://github.com/bufbuild/protoc-gen-validate/blob/a65858624dd654f2fb306d6af60f737132986f44/module/checker.go#L18
var httpHeaderValueRegexp = regexp.MustCompile("^[^\u0000-\u0008\u000A-\u001F\u007F]*$")

// ValidateHTTPHeaderValue validates a header value for Envoy
// Valid: "foo", "%HOSTNAME%", "100%%", "prefix %HOSTNAME% suffix"