examples: add examples/fetch_ip.v, showing how to contact http://ifconfig.co/json and parse the result

examples/fetch_ip.v

@@ -0,0 +1,41 @@
+import json
+import net.http
+
+struct IpInfo {
+	ip          string
+	ip_decimal  int
+	country     string
+	country_iso string
+	country_eu  bool
+	region_name string
+	region_code string
+	zip_code    string
+	city        string
+	latitude    f64
+	longitude   f64
+	time_zone   string
+	asn         string
+	asn_org     string
+	user_agent  UserAgent
+}
+
+struct UserAgent {
+	product   string
+	version   string
+	comment   string
+	raw_value string
+}
+
+url := 'http://ifconfig.co/json'
+resp := http.fetch(
+	url: url
+	user_agent: 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/117.0'
+) or {
+	eprintln('failed to fetch data from the server, error: ${err}')
+	exit(1)
+}
+ip_info := json.decode(IpInfo, resp.body) or {
+	println('failed to decode the json data returned by the server, error: ${err}')
+	exit(2)
+}
+println(ip_info)