[Rust] Added metric header to connection user properties (#598)

Author: cartertinney

rust/azure_iot_operations_mqtt/src/rumqttc_adapter.rs

@@ -267,6 +267,7 @@ pub fn client(
     connection_settings: MqttConnectionSettings,
     channel_capacity: usize,
     manual_ack: bool,
+    connection_user_properties: Vec<(String, String)>,
 ) -> Result<(rumqttc::v5::AsyncClient, rumqttc::v5::EventLoop), MqttAdapterError> {
     // NOTE: channel capacity for AsyncClient must be less than usize::MAX - 1 due to (presumably) a bug.
     // It panics if you set MAX, although MAX - 1 is fine.
@@ -277,6 +278,12 @@ pub fn client(
     }
     let mut mqtt_options: rumqttc::v5::MqttOptions = connection_settings.try_into()?;
     mqtt_options.set_manual_acks(manual_ack);
+
+    // Add any provided user properties
+    let mut existing_props = mqtt_options.user_properties();
+    existing_props.extend(connection_user_properties);
+    mqtt_options.set_user_properties(existing_props);
+
     Ok(rumqttc::v5::AsyncClient::new(
         mqtt_options,
         channel_capacity,

rust/azure_iot_operations_mqtt/src/session/wrapper.rs

@@ -58,6 +58,9 @@ pub struct SessionOptions {
     /// Maximum number of queued outgoing messages not yet accepted by the MQTT Session
     #[builder(default = "100")]
     pub outgoing_max: usize,
+    /// Indicates if the Session should use features specific for use with the AIO MQTT Broker
+    #[builder(default = true)]
+    pub aio_broker_features: bool,
 }
 
 impl Session {
@@ -68,8 +71,21 @@ impl Session {
     pub fn new(options: SessionOptions) -> Result<Self, SessionConfigError> {
         let client_id = options.connection_settings.client_id.clone();
         let sat_file = options.connection_settings.sat_file.clone();
-        let (client, event_loop) =
-            adapter::client(options.connection_settings, options.outgoing_max, true)?;
+
+        // Add AIO metric to user properties when using AIO MQTT broker features
+        // TODO: consider user properties from being supported on SessionOptions or ConnectionSettings
+        let user_properties = if options.aio_broker_features {
+            vec![("metriccategory".into(), "aiosdk-rust".into())]
+        } else {
+            vec![]
+        };
+
+        let (client, event_loop) = adapter::client(
+            options.connection_settings,
+            options.outgoing_max,
+            true,
+            user_properties,
+        )?;
         Ok(Session(session::Session::new_from_injection(
             client,
             event_loop,