add gmail app password example

examples/gmail_app_password.rs

@@ -0,0 +1,38 @@
+/// Example of using gmail authenticating using
+/// an [App Password](https://support.google.com/accounts/answer/185833)
+extern crate imap;
+extern crate native_tls;
+
+use native_tls::TlsConnector;
+
+fn main() {
+    let domain = "imap.gmail.com";
+    let port = 993;
+    let socket_addr = (domain, port);
+    let ssl_connector = TlsConnector::builder().build().unwrap();
+    let client = imap::connect(socket_addr, domain, &ssl_connector).unwrap();
+
+    let mut imap_session = match client.login("[email protected]", "<app_password>") {
+        Ok(c) => c,
+        Err((e, _unauth_client)) => {
+            println!("error authenticating: {}", e);
+            return;
+        }
+    };
+
+    match imap_session.select("INBOX") {
+        Ok(mailbox) => println!("{}", mailbox),
+        Err(e) => println!("Error selecting INBOX: {}", e),
+    };
+
+    match imap_session.fetch("2", "body[text]") {
+        Ok(msgs) => {
+            for msg in &msgs {
+                print!("{:?}", msg);
+            }
+        }
+        Err(e) => println!("Error Fetching email 2: {}", e),
+    };
+
+    imap_session.logout().unwrap();
+}